Code cleanup: Remove unneeded code
Added missing echo
Fix redirection to login page after install

When installation is started from login page (redirected to install from
core.php), the link to 'Continue to log into Mantis' goes back to
install page instead of login page.

Resolved problem by adding a no-cache header.

Also changed Location header response to 307 instead of default 302.

Fixes #16510
Remove wrong phpdoc tags
Fix system notice undefined variable days_old

Commit fbd654083f061fcfcc8dc7229953cc44737889fa added t_ prefix to some
variables, but did not replace all occurences of the old variable name,
causing SQL syntax error depending on filter

Fixes #16527
Remove unnecessary filter_ensure_valid_filter() call

user_get_bug_filter() already calls filter_ensure_valid_filter(), we
therefore only need to call it when unserializing the filter from token
Split long line to improve code readability
Fix data type mismatch when filtering by date

This was caused by inconsistent initialization of filter, which was set
to 'on' when checkbox was checked, and FALSE when unchecked. We now set
it to 'off' when unchecked.

Use of ternary operator to simplify code.

Fixes #16516
Fix whitespace
Additional fix #16039: Signup page causes error in web server log
Additional fix #16039: Lost password page causes error in web server log
Add progress messages to unattended upgrade script.
Oracle: fix errors in database API function names

Commit 321e03569fe163e101e737b585c31f22e7576510 renamed some functions
from original patch, to comply with MantisBT coding guidelines. This
fixes the following errors:
- one occurrence of order_binds_sequentially() was not renamed
  properly, and another was left with its original name
- db_oracle_adapt_query_syntax() was left with a trailing '_ora'

Fixes #16537