Remove duplicated ignition.py file.
Remove duplicated ignition.py file.

We had both inbox/ignition.py and inbox/models/ignition.py. All imports are
from inbox.ignition, not inbox.models.ignition, so remove the latter.

gale320/sync-engine,PriviPK/privipk-sync-engine,rmasters/inbox,closeio/nylas,EthanBlackburn/sync-engine,PriviPK/privipk-sync-engine,jobscore/sync-engine,ErinCall/sync-engine,wakermahmud/sync-engine,closeio/nylas,EthanBlackburn/sync-engine,nylas/sync-engine,PriviPK/privipk-sync-engine,gale320/sync-engine,wakermahmud/sync-engine,Eagles2F/sync-engine,jobscore/sync-engine,PriviPK/privipk-sync-engine,jobscore/sync-engine,ErinCall/sync-engine,PriviPK/privipk-sync-engine,Eagles2F/sync-engine,wakermahmud/sync-engine,EthanBlackburn/sync-engine,Eagles2F/sync-engine,gale320/sync-engine,rmasters/inbox,gale320/sync-engine,nylas/sync-engine,rmasters/inbox,wakermahmud/sync-engine,wakermahmud/sync-engine,ErinCall/sync-engine,Eagles2F/sync-engine,EthanBlackburn/sync-engine,Eagles2F/sync-engine,EthanBlackburn/sync-engine,gale320/sync-engine,ErinCall/sync-engine,closeio/nylas,nylas/sync-engine,ErinCall/sync-engine,jobscore/sync-engine,nylas/sync-engine,rmasters/inbox,closeio/nylas