rate_limit: Delete code handling impossible cases with request.user.
rate_limit: Delete code handling impossible cases with request.user.

I can find no evidence of it being possible to get an Exception when
accessing request.user or for it to be falsy. Django should always set
request.user to either a UserProfile (if logged in) or AnonymousUser
instance. Thus, this seems to be dead code that's handling cases that
can't happen.

rht/zulip,zulip/zulip,andersk/zulip,hackerkid/zulip,andersk/zulip,kou/zulip,andersk/zulip,rht/zulip,rht/zulip,showell/zulip,showell/zulip,punchagan/zulip,andersk/zulip,punchagan/zulip,kou/zulip,eeshangarg/zulip,hackerkid/zulip,eeshangarg/zulip,eeshangarg/zulip,kou/zulip,hackerkid/zulip,rht/zulip,rht/zulip,zulip/zulip,rht/zulip,showell/zulip,eeshangarg/zulip,eeshangarg/zulip,showell/zulip,eeshangarg/zulip,kou/zulip,punchagan/zulip,kou/zulip,punchagan/zulip,zulip/zulip,rht/zulip,zulip/zulip,showell/zulip,punchagan/zulip,kou/zulip,hackerkid/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,showell/zulip,zulip/zulip,zulip/zulip,hackerkid/zulip,hackerkid/zulip,hackerkid/zulip,showell/zulip,punchagan/zulip,zulip/zulip,punchagan/zulip,andersk/zulip