Post-merge fix: Silence warning due to type mismatch.

client/mysql_upgrade.c:
  Silence warning due to type mismatch.

client/mysql_upgrade.c

@@ -364,6 +364,8 @@ static void find_tool(char *tool_executable_name, const char *tool_name,
   }
   else
   {
+    int len;
+
     /*
       mysql_upgrade was run absolutely or relatively.  We can find a sibling
       by replacing our name after the LIBCHAR with the new tool name.
@@ -385,10 +387,10 @@ static void find_tool(char *tool_executable_name, const char *tool_name,
       last_fn_libchar -= 6;
     }
 
+    len= last_fn_libchar - self_name;
+
     my_snprintf(tool_executable_name, FN_REFLEN, "%.*s%c%s",
-             (last_fn_libchar - self_name), self_name, 
-             FN_LIBCHAR,
-             tool_name);
+                len, self_name, FN_LIBCHAR, tool_name);
   }
 
   verbose("Looking for '%s' as: %s", tool_name, tool_executable_name);