[task manager] Sync call stuck when rabbit-mq server is not running

[NajmudheenCT]

Issue/Feature Description:
Sync and sync-all requests stuck when we dont have rabbitmq-server is not installed or not running

---- log snippet -----

2020-05-22 17:33:22.214 28040 ERROR oslo.messaging._drivers.impl_rabbit [req-46d5d2ad-c0d4-4b7e-a692-659bf2eb138b - - - - -] Connection failed: [Errno 111] ECONNREFUSED (retrying in 2.0 seconds): ConnectionRefusedError: [Errno 111] ECONNREFUSED
2020-05-22 17:33:24.222 28040 ERROR oslo.messaging._drivers.impl_rabbit [req-46d5d2ad-c0d4-4b7e-a692-659bf2eb138b - - - - -] Connection failed: [Errno 111] ECONNREFUSED (retrying in 4.0 seconds): ConnectionRefusedError: [Errno 111] ECONNREFUSED
2020-05-22 17:33:24.982 28040 ERROR oslo.messaging._drivers.impl_rabbit [-] Connection failed: [Errno 111] ECONNREFUSED (retrying in 6.0 seconds): ConnectionRefusedError: [Errno 111] ECONNREFUSED

Why this issue to fixed / feature is needed(give scenarios or use cases):
User should get a failure response when rabbitmq-server is not connectable.
How to reproduce, in case of a bug:
stop rabbitmq-server and run /v1/storages//sync
Other Notes / Environment Information: (Please give the env information, log link or any useful information for this issue)

[NajmudheenCT]

install script is palnning a pre-check for this.. lowering priority for June

[NajmudheenCT]

Install script addresses the precheck , closing this issue