provide better error messages in a couple cases

git-svn-id: https://svn.apache.org/repos/asf/karaf/trunk@1102131 13f79535-47bb-0310-9956-ffa450edef68
Make sure the console thread for the non blocking input stream is correctly shut down
[KARAF-1572] JDBC Lock without using long running transactions
[KARAF-2633] Prevent deadlocks with classloaders on JDK 6