qga: move agent run in a separate function

qga: move agent run in a separate function

Once the options are populated, move the running state to
a run_agent() function.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
* fixed up an s/ga_state/s/ artifact causing segfault
* replaced g_list_free_full with g_list_foreach to maintain glib
  2.22 compatibility
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>