Fixes to Bugzilla exporter

- Don't break down if CSV contains only header row
- Don't keep on looping on the same date interval if 0 bugs are found.
  Instead, pass forward the used end date for next polling rounds
- Actually set the password to Bugzilla query, previously set the username
  also to password field
Updated dependencies
Commented out unused code

Still left there, may be something that's almost done and could be taken
in use. Needs to be checked.