Set smaller default timeout for streaming API.
Set smaller default timeout for streaming API.

Summary:
This timeout value is pretty arbitrary. But it has to be less than the
proxy_read_timeout configured in nginx (currently 3600s). Otherwise the proxy
may wrongly return 504s.

Fixes T934.

Test Plan: Not needed.

Reviewers: khamidou, spang

Reviewed By: spang

Subscribers: spang

Maniphest Tasks: T934

Differential Revision: https://review.inboxapp.com/D1301

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