Cannot delete Space/Project which was created by migration tool in RHDM/RHPAM

Issue

• After migrating .niogit from BPMS 6.4.0 to RHPAM 7.3.0 following this document,

https://access.redhat.com/documentation/en-us/red_hat_process_automation_manager/7.0/html-single/migrating_from_red_hat_jboss_bpm_suite_6.4_to_red_hat_process_automation_manager_7.0/index#migration-tool-7.0-con_non-exec-server

I can see migrated projects in spaces. Then, if I click "Delete Space" or "Delete Project", I get the following Exception so cannot delete the space/project.

14:35:41,876 ERROR [org.guvnor.structure.backend.repositories.RepositoryServiceImpl] (default task-11) Error while removing repositories: java.lang.RuntimeException: The ConfigType REPOSITORY requires a namespace.
    at org.guvnor.structure.backend.config.ConfigurationServiceImpl.resolveConfigGroupPath(ConfigurationServiceImpl.java:356)
    at org.guvnor.structure.backend.config.ConfigurationServiceImpl.removeConfiguration(ConfigurationServiceImpl.java:415)
    at org.guvnor.structure.backend.config.ConfigurationServiceImpl$Proxy$_$$_WeldClientProxy.removeConfiguration(Unknown Source)
    at org.guvnor.structure.backend.repositories.RepositoryServiceImpl.doRemoveRepository(RepositoryServiceImpl.java:411)
    at org.guvnor.structure.backend.repositories.RepositoryServiceImpl.removeRepositories(RepositoryServiceImpl.java:390)
    at org.guvnor.structure.backend.repositories.RepositoryServiceImpl$Proxy$_$$_WeldClientProxy.removeRepositories(Unknown Source)
    at org.guvnor.structure.backend.organizationalunit.OrganizationalUnitServiceImpl.removeOrganizationalUnit(OrganizationalUnitServiceImpl.java:503)
    at org.guvnor.structure.backend.organizationalunit.OrganizationalUnitServiceImpl$Proxy$_$$_WeldClientProxy.removeOrganizationalUnit(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        ...