subject caching issues

subject caching issues... can't run multiple grouper components on the same host since the subject cache file created is the same name for all components - the cache files will be different for each component - this was discussed in slack tier-grouper. Also this NPE was presented:

ui_1 | grouper-api;grouper_error.log;dev;ui;2019-02-17 01:03:30,178: [Thread-12] ERROR SubjectSourceCache.subjectSourceCacheThread(251) - - Error in sweepCacheToResolveItemsThatNeedIt
ui_1 | java.lang.NullPointerException
ui_1 | at edu.internet2.middleware.grouper.GrouperSourceAdapter$2.callback(GrouperSourceAdapter.java:318)
ui_1 | at edu.internet2.middleware.grouper.GrouperSession.callbackGrouperSession(GrouperSession.java:974)
ui_1 | at edu.internet2.middleware.grouper.GrouperSourceAdapter.getSubjectsByIds(GrouperSourceAdapter.java:311)
ui_1 | at edu.internet2.middleware.grouper.subj.cache.SubjectSourceCache.sweepCacheToResolveItemsThatNeedIt(SubjectSourceCache.java:161)
ui_1 | at edu.internet2.middleware.grouper.subj.cache.SubjectSourceCache.subjectSourceCacheThread(SubjectSourceCache.java:249)
ui_1 | at edu.internet2.middleware.grouper.subj.cache.SubjectSourceCache$1.run(SubjectSourceCache.java:218)
ui_1 | at java.lang.Thread.run(Thread.java:748)