unix: Remove assert in uv__pipe_accept
unix: Remove assert in uv__pipe_accept

This assert unnecessarily prevents people from using the pipe_wrap
class in node to send file descriptors over sockets.

unknownbrackets/maxcso,urbit/archaeology2,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,urbit/archaeology2,urbit/archaeology2,unknownbrackets/maxcso,urbit/archaeology2,unknownbrackets/maxcso,urbit/archaeology2,urbit/archaeology2,urbit/archaeology2,urbit/archaeology2,unknownbrackets/maxcso,urbit/archaeology2