xinetd: socket bind: Invalid argument (errno = 22) when using USERID on ipv6

copied from trunk

Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>
Merge pull request #319 from chris5560/for-14.07

for-14.07: xinetd: socket bind: Invalid argument (errno = 22) when using USERID on ...