SUNRPC: Don't create a gss auth cache unless rpc.gssd is running

An infinite loop is caused when nfs4_establish_lease() fails
with -EACCES. This causes nfs4_handle_reclaim_lease_error()
to sleep a bit and resets the NFS4CLNT_LEASE_EXPIRED bit.
This in turn causes nfs4_state_manager() to try and
reestablished the lease, again, again, again...

The problem is a valid RPCSEC_GSS client is being created when
rpc.gssd is not running.

Link: http://lkml.kernel.org/r/1392066375-16502-1-git-send-email-steved@redhat.com
Fixes: 0ea9de0ea6a4 (sunrpc: turn warn_gssd() log message into a dprintk())
Reported-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

net/sunrpc/auth_gss/auth_gss.c

@@ -991,6 +991,8 @@ gss_create_new(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 	gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
 	if (gss_auth->service == 0)
 		goto err_put_mech;
+	if (!gssd_running(gss_auth->net))
+		goto err_put_mech;
 	auth = &gss_auth->rpc_auth;
 	auth->au_cslack = GSS_CRED_SLACK >> 2;
 	auth->au_rslack = GSS_VERF_SLACK >> 2;