OAK-1200 occasional test failure in org.apache.jackrabbit.mk.store.DefaultRevisionStoreTesttestConcurrentMergeGC
OAK-587 DefaultRevisionStoreTest.testConcurrentGC fails every now and then.
OAK-107 testConcurrentMergeGC fails intermittently
@Ignore offending test again

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1543451 13f79535-47bb-0310-9956-ffa450edef68