d/control: bump standars to 3.9.7

No changes required, per checklist:
 https://www.debian.org/doc/packaging-manuals/upgrading-checklist.txt

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>

debian/control

@@ -16,7 +16,7 @@ Build-Depends: autoconf,
                libnfnetlink-dev,
                libnftnl-dev,
                libtool (>= 2.2.6)
-Standards-Version: 3.9.6
+Standards-Version: 3.9.7
 Homepage: http://www.netfilter.org/
 Vcs-Git: https://alioth.debian.org/anonscm/git/pkg-netfilter/pkg-netfilter.git
 Vcs-Browser: https://alioth.debian.org/plugins/scmgit/cgi-bin/gitweb.cgi?p=pkg-netfilter/pkg-netfilter.git