SUNRPC: AUTH_SYS "machine creds" shouldn't use negative valued uid/gid

Apparently this causes Solaris 10 servers to refuse our NFSv4 SETCLIENTID
calls. Fall back to root creds for now, since most servers that care are
very likely to have root squashing enabled.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/auth_generic.c

@@ -17,8 +17,8 @@
 # define RPCDBG_FACILITY	RPCDBG_AUTH
 #endif
 
-#define RPC_ANONYMOUS_USERID	((uid_t)-2)
-#define RPC_ANONYMOUS_GROUPID	((gid_t)-2)
+#define RPC_MACHINE_CRED_USERID		((uid_t)0)
+#define RPC_MACHINE_CRED_GROUPID	((gid_t)0)
 
 struct generic_cred {
 	struct rpc_cred gc_base;
@@ -44,8 +44,8 @@ EXPORT_SYMBOL_GPL(rpc_lookup_cred);
 struct rpc_cred *rpc_lookup_machine_cred(void)
 {
 	struct auth_cred acred = {
-		.uid = RPC_ANONYMOUS_USERID,
-		.gid = RPC_ANONYMOUS_GROUPID,
+		.uid = RPC_MACHINE_CRED_USERID,
+		.gid = RPC_MACHINE_CRED_GROUPID,
 		.machine_cred = 1,
 	};