MINOR: dns: dns_connect_nameserver: fix fd leak at error path

MINOR: dns: dns_connect_nameserver: fix fd leak at error path

This fixes the commit 2c7e05f80e3b
("MEDIUM: dns: don't call connect to dest socket for AF_INET*"). If we fail to
bind AF_INET sockets or the address family of the nameserver protocol isn't
something, what we expect, we need to close the fd, obtained by
connect.

This fixes the issue GitHub #3085
This must be backported along with the commit 2c7e05f80e3b.