Fix build failure against recent network update

[13 of 20] Compiling Net              ( src/Net.hs, dist/build/mighty/mighty-tmp/Net.o )

src/Net.hs:28:14:
    Ambiguous occurrence `sClose'
    It could refer to either `Network.sClose',
                             imported from `Network' at src/Net.hs:4:1-14
                          or `Network.Socket.sClose',
                             imported from `Network.Socket' at src/Net.hs:6:1-21

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>