Corrected format string for long long thread_id

This is expected to fix many test failures on 32bit builds where creation of
second temporary table was failing.

sql/sql_table.cc

@@ -573,7 +573,7 @@ uint build_tmptable_filename(THD* thd, char *buff, size_t bufflen)
   DBUG_ENTER("build_tmptable_filename");
 
   char *p= strnmov(buff, mysql_tmpdir, bufflen);
-  my_snprintf(p, bufflen - (p - buff), "/%s%lx_%lx_%x",
+  my_snprintf(p, bufflen - (p - buff), "/%s%lx_%llx_%x",
               tmp_file_prefix, current_pid,
               thd->thread_id, thd->tmp_table++);