Fix sonar issues in feature-state-management

Fix sonar issues in feature-state-management

DroolsPDPIntegrityMonitor.java:
Modified init() to throw just IntegrityMonitorException.
Modified DroolsPDPIntegrityMonitor init() method to throw specific
types of exceptions.

StateManagementFeature.java:
Sonar complained about needing to merge "if" statements, but chose
to eliminate the "if(logger.isDebugEnabled())" instead - did this
through-out the source file.
Removed extra runtime exception from "throws" declaration.

DbAudit.java:
Fixed sonar issue regarding setting a static variable from within
a non-static method.
Removed logger.isDebugEnabled() tests where method calls are not involed.
Simplified invoke() method complexity as reported by sonar.

DroolsPDPIntegrityMonitor.java:
Reduced init() complexity reported by sonar.

Change-Id: Ib2722b21bbf3aad130af46c8790f40d8777e36be
Issue-ID: POLICY-469
Signed-off-by: Jim Hahn <jrh3@att.com>