ACCUMULO-2120 Plugin declarations belong in pluginManagement not as a dependency.

Move the delcaration of the plugin out of dependencyManagement
and into pluginManagement. Pull the configuration (skipNoGit)
into that plugin declaration in pluginManagement.
Merge branch '1.4.5-SNAPSHOT' into 1.5.1-SNAPSHOT

Conflicts:
	pom.xml
Merge branch '1.5.1-SNAPSHOT' into 1.6.0-SNAPSHOT

Conflicts:
	pom.xml
Merge branch '1.6.0-SNAPSHOT'