Add XMLRPC Fault exception to retry decorator

[amcmahon-rh]

We have seen several cases where Pub tasks fail because the worker gets a permission denied error, immediately after successfully logging in. We believe that these are false negatives, which can be resolved by a simple retry.

[rbikar]

@amcmahon-rh can you please add/update some test that covers this part?

[kdudka]

When xmlrpclib.ProtocolError was added in the list via #173, it caused a regression in OSH, reported as #270, which has not yet been fixed. I am afraid that adding xmlrpclib.Fault may have similar undesired side effects.

[amcmahon-rh]

@kdudka would you be ok with this change if the xmlrpclib.Fault handling was restricted to permission denied errors specifically?

Something like:

                except (socket.error, socket.herror, socket.gaierror, socket.timeout,
                        httplib.CannotSendRequest, xmlrpclib.ProtocolError,
                        xmlrpclib.Fault) as ex:
                    if type(ex) is xmlrpclib.Fault and \
                            not "PermissionDenied" in ex.faultString:
                        raise ex

[kdudka]

Yes, making the condition to retry the request more specific sounds like a good idea.