Errors when subscribing/unsubscribing/sorting config channels in activation key after one of the config channels was deleted

Issue

• After deleting one of the config channels, activation key does not show correct config channel ranks (e.g., 1 and 3 when it should be 1 and 2)

• Trying to subscribe activation key to a new config channel or view/modify existing config channel rankings results in Internal Server Error and following stacktrace in /var/log/tomcat5/catalina.out:

  ...
  java.lang.NullPointerException
          at com.redhat.rhn.frontend.action.token.configuration.RankChannelsAction.populateWidgetLabels(RankChannelsAction.java:236)
          at com.redhat.rhn.frontend.action.token.configuration.RankChannelsAction.setupWidget(RankChannelsAction.java:87)
          at com.redhat.rhn.frontend.action.token.configuration.RankChannelsAction.setup(RankChannelsAction.java:223)
          at com.redhat.rhn.frontend.action.token.configuration.RankChannelsAction.init(RankChannelsAction.java:164)
          at com.redhat.rhn.frontend.action.token.configuration.RankChannelsAction.execute(RankChannelsAction.java:68)
          at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
          ... 40 more
  ...
  

• Trying to unsubscribe from one of the config channels results in Internal Server Error and following stacktrace in /var/log/tomcat5/catalina.out:

  ...
  java.lang.NullPointerException
          at com.redhat.rhn.domain.config.ConfigChannel.equals(ConfigChannel.java:248)
          at java.util.ArrayList.indexOf(ArrayList.java:461)
          at java.util.ArrayList.remove(ArrayList.java:570)
          at org.hibernate.collection.PersistentList.remove(PersistentList.java:156)
          at com.redhat.rhn.domain.config.ConfigChannelListProcessor.remove(ConfigChannelListProcessor.java:98)
          at com.redhat.rhn.frontend.action.token.configuration.ListRemoveChannelsAction.handleDispatch(ListRemoveChannelsAction.java:62)
          at com.redhat.rhn.frontend.action.token.BaseListAction.execute(BaseListAction.java:90)
          at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
          ... 40 more
  ...