Don't stop neo data source in case of failure

when switching to slave, because it will prevent future switch tries with
NPE in CommonAbstractStore.
Merge pull request #1853 from tinwelint/1.9-slave-switch-retry-thingie

Don't stop neo data source in case of failure
Adds test for Monitors and fixes issue with listener removal

The test MonitorsTest.shouldUnregister() was failing with a ClassCastException.
 The reason was that it was doing the cast on a field different than the one that
 it was performing the instanceof check.

Conflicts:
	community/kernel/src/test/java/org/neo4j/kernel/monitoring/MonitorsTest.java
Merge branch 'neo4j/1.9-maint' into master

Conflicts:
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/cluster/HighAvailabilityModeSwitcher.java
Merge pull request #1868 from cleishm/2.0-merge-1.9-maint

Merge branch 'neo4j/1.9-maint' into master