#91 Allow for removing of additional fields

[Kim Hornung]

You can already remove priority, os and severity from
the bug form. I would like to be able to remove
additional fields that I don't use:
- site
- database

This can be done by adding the following lines to
bug.php (approx. line 472 in bug.php v 1.120)
v 1.120:
$site = $site ? $site : 0;
$database = $database ? $database : 0;