libxtables12: breaks and replaces libxtables11

[...]
Preparing to unpack .../libxtables12_1.6.0+snapshot20161117-2_amd64.deb ...
Unpacking libxtables12:amd64 (1.6.0+snapshot20161117-2) ...
dpkg: error processing archive
/var/cache/apt/archives/libxtables12_1.6.0+snapshot20161117-2_amd64.deb
(--unpack):
 trying to overwrite '/usr/lib/x86_64-linux-gnu/libxtables.so.12.0.0',
which is also in package libxtables11:amd64 1.6.0+snapshot20161117-1
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Errors were encountered while processing:
 /var/cache/apt/archives/libxtables12_1.6.0+snapshot20161117-2_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
[...]

Closes: #845278
Signed-off-by: Arturo Borrero Gonzalez <arturo@debian.org>

debian/control

@@ -56,8 +56,8 @@ Architecture: linux-any
 Priority: optional
 Section: libs
 Depends: ${misc:Depends}, ${shlibs:Depends}
-Replaces: iptables (<< 1.4.16.3-3)
-Breaks: iptables (<< 1.4.16.3-3)
+Replaces: iptables (<< 1.4.16.3-3), libxtables11 (<< 1.6.0+snapshot20161117-1)
+Breaks: iptables (<< 1.4.16.3-3), libxtables11 (<< 1.6.0+snapshot20161117-1)
 Description: netfilter xtables library
  The user-space interface to the Netfilter xtables kernel framework.