heat tests : test_watch add tests for set_watch_state

Add some tests providing coverage for the set_watch_state function

Change-Id: Ia9f418035440c0941e25dd2e1ec85f8c0322d807
Signed-off-by: Steven Hardy <shardy@redhat.com>
heat engine : make WatchRule initial state NODATA

Initial state should be NODATA not NORMAL, as we've not
done any metric evaluation until the first evaluation
period has elapsed

fixes bug 1102446

Change-Id: Ic41df29c00a5df2f3d161bc1b1d054d816c5afa5
Signed-off-by: Steven Hardy <shardy@redhat.com>