Add skeleton unit tests for app server subclasses

Change-Id: I75373c63b0b4d80e317208446c3addca07d1f110
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Reviewed-on: http://review.gluster.org/5083
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>