Add usecplugin features

1) Feature Tests Pass: https://jenkins.opendaylight.org/releng/view/usecplugin/job/usecplugin-distribution-boron/
2) Features Comply with Guidelines: https://git.opendaylight.org/gerrit/gitweb?p=usecplugin.git;a=blob;f=features/src/main/features/features.xml
	a) Feature Names: odl-usecplugin-aaa, odl-usecplugin-openflow
	b) Features Descriptions: Present
	c) Features Start-Levels: NA
3) Features Tested: Features have been tested for functionality with
	a) feature:install odl-usecplugin-aaa odl-usecplugin-openflow
	b) feature:install odl-usecplugin-aaa odl-usecplugin-openflow, feature:install odl-integration-compatible-with-all
4) Integration Test Impact: Nil

Change-Id: Ica9b99f2c1b9026900e96cfd274be396beb0be8a
Signed-off-by: thomaslees <thomaslee.s@tcs.com>