refactor snmp peer factory more, fix a deadlock in the access service
Merge remote-tracking branch 'origin/1.12'

Conflicts:
	opennms-config/pom.xml
	opennms-config/src/main/java/org/opennms/netmgt/config/SnmpConfigAccessService.java
	opennms-config/src/main/java/org/opennms/netmgt/config/SnmpPeerFactory.java
	opennms-config/src/test/java/org/opennms/netmgt/config/ConfigureSnmpTest.java
	opennms-webapp/src/main/java/org/opennms/web/rest/OnmsRestService.java