Tolerate failure on ipv6 tcp server test and add ipv4 version
Tolerate failure on ipv6 tcp server test and add ipv4 version

(needed for Travis tests which seem to have broken ipv6 support)

luvit/luv,zhaozg/luv,joerg-krause/luv,joerg-krause/luv,zhaozg/luv,luvit/luv