GatewayCommunicator: fix ERRFMT in logging statistics
GatewayCommunicator: fix ERRFMT in logging statistics

Size of readable queue is represented as unsinged long and that
does not fit in %d. This caused invalid output:

[Notice] active connections: 1, readable queue: [ERRFMT],
thread pool allocated: 1, available: 63, capacity: 64

Also __FILE__ and __LINE__ parameters were missing, so rewriting
of the whole message was needed.

Fixes: 36b6039833b1 ("GatewayCommunicator: new class")
Signed-off-by: Jozef Halaj <d60338334aa79f5c61824693142b417ad5db682f@stud.fit.vutbr.cz>
Acked-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server