logUtils.funcName: work on partial methods

misc.Event.emit() fails when its callback is a partial(method, args) as
it is neither a method, nor has func_name.

Thread-645::WARNING::2013-01-24 01:29:11,212::misc::1236::Event.Storage.DomainMonitor.onDomainConnectivityStateChange::(_emit) Could not run registered method because of an exception
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/misc.py", line 1228, in _emit
    logUtils.funcName(func))
  File "/usr/share/vdsm/logUtils.py", line 31, in funcName
    return func.func_name
AttributeError: 'functools.partial' object has no attribute 'func_name'

Change-Id: I59ce729edadc57b5df4eee8860d96367d9ed8253
Signed-off-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/11305
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Saggi Mizrahi <smizrahi@redhat.com>