open_socket_in was attempting to try all the protocols returned from

getaddrinfo(), but only if a corresponding call to socket() returned one of
three *NOSUPPORT errno codes.  A Redhat 6.2 system was observed returning
EINVAL instead so it never went on to try IPv4.  This update adds EINVAL to
the list.  Question: why not always continue through the list regardless of
what errno is?