libxtables12: fix Replaces and Breaks relationships

The problem with this package and libxtables11 not being co-installable
was introduced in the first snapshot version which did not get the
SONAME bumped for the package name. But older versions should still be
co-installable as they have different SONAMES. Change the direction
of the verioned dependencies to cover this.

In addition using a >= should be safe here as long as a libxtables11
is not reintroduced.

Closes: #845800
Signed-off-by: Guillem Jover <guillem@debian.org>
Signed-off-by: Arturo Borrero Gonzalez <arturo@debian.org>

debian/control

@@ -55,8 +55,8 @@ Architecture: linux-any
 Priority: optional
 Section: libs
 Depends: ${misc:Depends}, ${shlibs:Depends}
-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)
+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.