libvirt: Moving remove_guest to libvirt test dir

Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

tests/remove_guest.py

-from autotest.client.shared import error
-
-
-@error.context_aware
-def run_remove_guest(test, params, env):
-    """
-    everything is done by client.virt module
-    """
-    pass