fixes a bug when queue_server launched after a crawl start message, now ignores old message rather than give a php warning, a=chris

Author	Chris Pollett <chris@pollett.org>
Author date	2011-08-22 05:Aug:nd
Author local date	2011-08-21 22:Aug:st -0700
Committer	Chris Pollett <chris@pollett.org>
Committer date	2011-08-22 05:Aug:nd
Committer local date	2011-08-21 22:Aug:st -0700
Commit	10b9446424e8780d2885e6d503723ea930cd242a
Tree	f859bede62540f9605db58ccff18082a8dd102fb
Parent	17a10709dc15564f7226be9e71b1ba978fc43495

fixes a bug when queue_server launched after a crawl start message, now ignores old message rather than give a php warning, a=chris

Affected files:
controllers/admin_controller.php
lib/crawl_daemon.php