network: Fix resolv.conf reloading

resolv.conf is only reload by glibc on the first lookup request. This
leads to problems in cases where resolv.conf changes between after the
first lookup request, because the changes are not picked up by glibc.
E.g. any new or change nameserver will not be picked up, if resolv.conf
changed during one python process.

See also:
http://www.redhat.com/archives/rhl-devel-list/2009-January/msg01256.html

Change-Id: I1a89bd1bbc4bcf650af7539a8bf4cab8c43eaca1
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>