Fix warnings and error VC++ compiler

client/mysql.cc:
  Removing unreferenced variables
sql/sql_test.cc:
  Fix VC++ compiler error that doesn't permits the declaration and
  initialization of variables that can be skipped by the prior
  goto end instruction.

client/mysql.cc

@@ -1414,7 +1414,6 @@ static int com_server_help(String *buffer __attribute__((unused)),
     server_cmd= cmd_buf;
   }
 
-  char buff[16], time_buf[32];
   MYSQL_RES *result;
   ulong timer;
   uint error= 0;