Fix regression in test_langs.php

Commit 78cee358 added file Web.config to plugins and lang folder.
test_langs.php treated the file as a plugin folder and a language file.
Merge branch 'fix13-test_langs' of github.com:atrol/mantisbt into atrol-fix13-test_langs
Fix #17510: regression in test_langs.php
Remove use of AS keyword from sql query in tag api.

In general, in the mantis code base, we do not add 'as' for tables,
and some database engines do not support AS in this context.