Disable django's debug mode for the collect command

Django will cache all SQL queries in memory when running in debug mode.
This uses up a lot of memory, so work-around that by disabling debug mode
for the collect command.
Call django.db.reset_queries after each legislator has been processed

Django will normally call that function when a request finishes processing.
For the collect command that won't be done, of course, since there are no
requests, so do it manually.