This patch adds a new zaqar.use_websockets option which if set to True
in the config file will configure the Zaqar collector to use
the websocket transport instead of wsgi. This can be more efficient
where you want to avoid the continuous polling of o-c-c and instead
just listen on the websocket that is subscribed to a queue.
Like other collectors each iteration creates a new socket object. This
allows us to use the normal re-exec logic in o-c-c and thus gives
the option to re-configure the agent in the future to use other types
of collectors. We could (optionally) look into a higher level option in
the future that would allow o-c-c to avoid re-exec'ing and thus re-use
the same websocket for multiple sets of metadata.
Depends-On: Ia2a8deb599252d8308e44d595eb2bf443999aaad
Change-Id: Id5c7ed590df776844b6c7961eb40f89206cd24e0
b6364df3e5