libwebsockets

client: suppress CONNECTION_ERROR if still in client_connect_via_info

If the client connection attempt fails early, we report it will a NULL
return from the client connection api.  If it fails later, perhaps after
more times around the event loop, we report it as a CONNECTION_ERROR.

This patch makes sure we don't do CONNECTION_ERROR flow if in fact we
are still in the client_connect_via_info() and in a position to report
the failure by returning NULL from there, without it under some
conditions we will do both a CONNECTION_ERROR and return NULL.