a bit more cleanup for SPC-690
Revert "a bit more cleanup for SPC-690"

This reverts commit fe5023896312ef8c0804972590a629a1c800fb18.
master has equals and hashCode, put it here and clean it up
SPC-690 isolate concurrent access better
Merge remote-tracking branch 'opennms/1.12'

Conflicts:
	opennms-services/src/main/java/org/opennms/netmgt/linkd/AtInterface.java
	opennms-services/src/main/java/org/opennms/netmgt/linkd/DiscoveryLink.java
	opennms-services/src/main/java/org/opennms/netmgt/linkd/Linkd.java