Bug 1087068 - [Loop] Long latency from the call is established to the 1st remote video is rendered 

See bug https://bugzilla.mozilla.org/show_bug.cgi?id=1087068 please.

Action happens at https://github.com/jaoo/firefoxos-loop-client/tree/1087068.
We could reduce this timing to get a more accurate polling. Move this to a `const`