aaa: use runVdsCommand

Use runVdsCommand instead of
[Backend.getInstnace()/getBackend()].getResourceManager().RunVdsCommand

Topic: AAA
Change-Id: Idcf48db5ea278a74b1bf87076d3b16af29bb416c
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>