fix typo in version mismatch msg

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

libc/inet/rpc/rpc_prot.c

@@ -219,7 +219,7 @@ rejected (enum reject_stat rjct_stat,
 {
   switch (rjct_stat)
     {
-    case RPC_VERSMISMATCH:
+    case RPC_MISMATCH:
       error->re_status = RPC_VERSMISMATCH;
       return;
     case AUTH_ERROR: