Bump kmscon version to 8

We're ready for a new bugfix release. Bump version to 8. No libraries are
installed, anymore, so no need to bump library versions.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

configure.ac

@@ -6,7 +6,7 @@
 AC_PREREQ(2.68)
 
 AC_INIT([kmscon],
-        [7],
+        [8],
         [http://bugs.freedesktop.org/enter_bug.cgi?product=kmscon],
         [kmscon],
         [http://www.freedesktop.org/wiki/Software/kmscon])