wrong assertion test for wsi->sock

[mhaberler]

the test in https://github.com/warmcat/libwebsockets/blob/master/lib/libwebsockets.c#L116 doesnt make sense

file descriptor 0 is legit after an accept - in particular you will get this if you have a demon-type setup where stdin, stdout stderr are typically closed. The way fd's are recycled you will get fd 0 on first accept after closing stdin.

suggestion: remove or mark an invalid fd as < 0.

[warmcat]

You were right. This got refactored into check against == LWS_INVALID_FILE a while ago.