Make debuild happy by including a date in debian/changelog

The previous commit resolved the debian build problem, but was building
packages with the stable version.  A development version is required in
the changelog to properly build development DEB packages.

packaging/debian/changelog

+ansible (1.8) unstable; urgency=low
+
+  * 1.8 release (PENDING)
+
+ -- Michael DeHaan <michael@ansible.com>  Wed, 21 Oct 2015 04:29:00 -0500
+
 ansible (1.7) unstable; urgency=low
 
   * 1.7.0 release