Production release 4.9.30

Fixed bugs:

• NoMethodError: undefined method `valid_password?' for nil:NilClass #1082

Closed issues:

• Sidekiq: high & low priority queues #1078

Merged pull requests:

• Limit low priority queue to 1 thread per process #1084 (irees)
• when creating a session, make sure that user is found #1083 (drewda)
• Workers: use GTFS_TMPDIR_BASEPATH #1081 (irees)
• Dist calc recursion #1077 (doublestranded)