It should be possible to pass GET parameters to +filebug

What happens:
Say you visit http://bugs.launchpad.net/malone/+filebug?field.tag=spam. You enter a title, check for dupes, find none that suit and then decide to file a new bug. However, the "tags" field is blank and you have to fill it in manually.

What should happen:
The GET params passed to +filebug (field.tag, field.title, etc) should be passed on to the filebug form when it's created.