gssapi: gss_compare_name() both ways (#503)

In the case that one name has no MNs and the second name only has an MN, then
the order in which the two names are passed in matters, but it shouldn't. Run
the comparison both ways.

lib/gssapi/mech/gss_compare_name.c

@@ -68,6 +68,19 @@ gss_compare_name(OM_uint32 *minor_status,
 						name_equal));
 			}
 		}
+		HEIM_SLIST_FOREACH(mn2, &name2->gn_mn, gmn_link) {
+			OM_uint32 major_status;
+
+			major_status = _gss_find_mn(minor_status, name1,
+						    mn2->gmn_mech_oid, &mn1);
+			if (major_status == GSS_S_COMPLETE && mn1) {
+				return (mn2->gmn_mech->gm_compare_name(
+						minor_status,
+						mn2->gmn_name,
+						mn1->gmn_name,
+						name_equal));
+			}
+		}
 		*name_equal = 0;
 	}