promote: Delete unused functions.

promotion_key, fuzz_impressions, campaign_lock, complimentary.
PromotionWeights.get_campaigns can filter by link and sr_names.
make_daily_promotions: delete test mode.
Stop using LiveAdWeights.
Delete LiveAdWeights.
Cleanup house ads query.
Don't worry about everything failing in promote.
promote: cleanup.

Consolidate duplicated logic and make methods more direct. There were
many monolithic methods that did many things and were called all over
the place when the desired action was just one piece of the method.
make_daily_promotions only runs for current time.

Specifying an offset would cause the wrong campaigns to go live.
Basic support for house priority campaigns.
promote.py: remove unused imports.
promote.py: Delete unneeded wrap_promoted and sponsor_wrapper.
Update all_live_promo_srnames when needed.
PromoCampaign: add default value for trans_id.
authorize: Add exception handling to is_charged_transaction.