Incoming calls with no call flow crash every other active call

[matiasgarciaisaia]

In Verboice 3.3.3, with a SIP Client channel that has no call flow assigned but its direction is (mistakenly) Both directions, getting an incoming call raises an exception in the broker, and then every call that was active fails with a Fatal Internal Error: {shutdown, {gen_server,call, [<0.2941.8>, {execute, ["STREAM FILE \"", "verboice/53d3699683def148265389d513e127cdfb235791", "\" \"",[],"\""]}, infinity]}} error (or a similar one with WAIT FOR DIGIT instead of STREAM FILE).

We discovered this issue in a broker handling a single channel, so we don't know if calls from a different channel would also fail or not.

A call failing shouldn't affect other calls.

[matiasgarciaisaia]

Related with #843