.vdb can't be modified connection type via change-vdb-connection-type of cli by NPE

Issue

• NullPointerException occurred when changing connection type via CLI.

[standalone@localhost:9999 /] /subsystem=teiid:change-vdb-connection-type(vdb-name=proc,vdb-version=1,connection-type=ANY)
{
    "outcome" => "failed",
    "failure-description" => "JBAS014749: Operation handler failed: java.lang.NullPointerException",
    "rolled-back" => true
}

The following stacktrace would be appeared on server.log.

ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 2) JBAS014612: Operation ("change-vdb-connection-type") failed - address: ([("subsystem" => "teiid")]): java.lang.NullPointerException
    at com.ctc.wstx.sw.BaseStreamWriter.writeCharacters(BaseStreamWriter.java:451)
    at org.teiid.adminapi.impl.VDBMetadataParser.writeElement(VDBMetadataParser.java:654)
    at org.teiid.adminapi.impl.VDBMetadataParser.writeDataPolicy(VDBMetadataParser.java:521)
    at org.teiid.adminapi.impl.VDBMetadataParser.writeVDB(VDBMetadataParser.java:492)
    at org.teiid.adminapi.impl.VDBMetadataParser.marshell(VDBMetadataParser.java:451)
    at org.teiid.jboss.VDBService.save(VDBService.java:512)
    at org.teiid.jboss.VDBService.access$300(VDBService.java:81)
    at org.teiid.jboss.VDBService$2.connectionTypeChanged(VDBService.java:204)
    at org.teiid.deployers.RuntimeVDB.changeConnectionType(RuntimeVDB.java:119)
    at org.teiid.jboss.ChangeVDBConnectionType.executeOperation(TeiidOperationHandler.java:1261)
    at org.teiid.jboss.ChangeVDBConnectionType.executeOperation(TeiidOperationHandler.java:1247)
    at org.teiid.jboss.BaseOperationHandler$1.execute(BaseOperationHandler.java:79)
    at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:710) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.AbstractOperationContext.doCompleteStep(AbstractOperationContext.java:545) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.AbstractOperationContext.completeStepInternal(AbstractOperationContext.java:338) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:314) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1152) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:335) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:204) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.doExecute(ModelControllerClientOperationHandler.java:209) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.access$300(ModelControllerClientOperationHandler.java:136) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:158) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:154) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at java.security.AccessController.doPrivileged(Native Method) [rt.jar:1.8.0_131]
    at javax.security.auth.Subject.doAs(Subject.java:422) [rt.jar:1.8.0_131]
    at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:94) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1.execute(ModelControllerClientOperationHandler.java:154) [jboss-as-controller-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.protocol.mgmt.AbstractMessageHandler$ManagementRequestContextImpl$1.doExecute(AbstractMessageHandler.java:364) [jboss-as-protocol-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at org.jboss.as.protocol.mgmt.AbstractMessageHandler$AsyncTaskRunner.run(AbstractMessageHandler.java:473) [jboss-as-protocol-7.5.18.Final-redhat-1.jar:7.5.18.Final-redhat-1]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [rt.jar:1.8.0_131]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [rt.jar:1.8.0_131]
    at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_131]
    at org.jboss.threads.JBossThread.run(JBossThread.java:122) [jboss-threads-2.1.2.Final-redhat-1.jar:2.1.2.Final-redhat-1]