svcrpc: set cr_gss_mech from gss-proxy as well as legacy upcall

The change made to rsc_parse() in
0dc1531a "svcrpc: store gss mech in
svc_cred" should also have been propagated to the gss-proxy codepath.
This fixes a crash in the gss-proxy case.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

net/sunrpc/auth_gss/svcauth_gss.c

@@ -1180,6 +1180,7 @@ static int gss_proxy_save_rsc(struct cache_detail *cd,
 		gm = gss_mech_get_by_OID(&ud->mech_oid);
 		if (!gm)
 			goto out;
+		rsci.cred.cr_gss_mech = gm;
 
 		status = -EINVAL;
 		/* mech-specific data: */
@@ -1195,7 +1196,6 @@ static int gss_proxy_save_rsc(struct cache_detail *cd,
 	rscp = rsc_update(cd, &rsci, rscp);
 	status = 0;
 out:
-	gss_mech_put(gm);
 	rsc_free(&rsci);
 	if (rscp)
 		cache_put(&rscp->h, cd);