userns: Convert group_info values from gid_t to kgid_t.

As a first step to converting struct cred to be all kuid_t and kgid_t
values convert the group values stored in group_info to always be
kgid_t values.   Unless user namespaces are used this change should
have no effect.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/net/sunrpc/auth_generic.c b/net/sunrpc/auth_generic.c
index 75762f3..6ed6f20 100644
--- a/net/sunrpc/auth_generic.c
+++ b/net/sunrpc/auth_generic.c
@@ -160,8 +160,8 @@
 	if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
 		goto out_nomatch;
 	for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
-		if (GROUP_AT(gcred->acred.group_info, i) !=
-				GROUP_AT(acred->group_info, i))
+		if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
+				GROUP_AT(acred->group_info, i)))
 			goto out_nomatch;
 	}
 out_match: