jsonrpc: Accept all stomp commands

Protocol detector needs to accept all stomp commands. The connection can
be lost at any time with the engine so we need to make sure that we
still accept incoming connections from the engine.

Bug-Url: https://bugzilla.redhat.com/1115044
Change-Id: Ie0469376abc3097d2fe82521b11db8a15f839c50
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>
Reviewed-on: http://gerrit.ovirt.org/29881
Reviewed-by: Dan Kenigsberg <danken@redhat.com>