Updated to Socket.IO v1 api in case of active signalmaster's maxClients configuration

[scotu]

Just a trivial fix for Socket.IO v1, I encountered the bug using maxClients in the config. I wasn't sure if it's good to return 0 if the room is not valid (because I'm not sure how it can happen that is not valid).

Let me know if I need to adjust anything.

(Thanks for signalmaster, btw :D)

[weinrank]

This doesn't work for me:
room.length is always undefined.
You should use Object.keys(room).length instead of room.length

Otherwise clientsInRooms is always 0;

[scotu]

My "fix" was indeed wrong. I updated the pr, I also noticed that to get the room, in other functions in signalmaster, the namespace was selected manually, so I went that way also here.

Let me know any further problems or requirements

Thanks