BUG: Drop unnecessary MySql-style quotes from SQL queries.

PostgreSQL throws syntax errors on names in backquotes.
BUG: Fix undefined variable usage in test viewer.

This commit fixes the following issue:

  PHP Notice:  Undefined variable: extras in /var/www/cdash/viewTest.php on line 273,
  referer: http://localhost/cdash/viewTest.php?buildid=391
BUG: Fix seeming logout in file viewer.