mount: revert recent fix for build problems on old systems

Revert the patch that added local definitions of AI_ADDRCONFIG and
friends to utils/mount/network.c.  While old header versions don't
have those flags, even older versions of getaddrinfo(3) don't
support those flags at all.

The result is this error:

  mount.nfs: DNS resolution failed for 10.10.10.10: Bad value for ai_flags

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>