Bugzilla: Removed unused glibc specific flags.

[Carlos O'Donell]

I've removed the backport, testsuite, and examined flags
from bugzilla.

Summarizing my comments here:
http://sourceware.org/ml/libc-alpha/2012-02/msg00726.html

* backport is better served with a keyword that requests
  exactly which branch to backport to.

* testsuite is a yes/no status, and better served by
  a keyword.

* examined is not required, we should be using last
  confirmed on date.

We have one flag in place today and it's "review" which
allows you to ask multiple people to review an issue.

Keywords have the down-side that they are harder for
a new user to use, but also much simpler than flags.

I've updated the procedures here:
http://sourceware.org/glibc/wiki/Bugzilla%20Procedures

Cheers,
Carlos.