Create debian changelog from git commits when building.

debian/changelog

+dcpman (0.1.2~2.gbp1e5230) UNRELEASED; urgency=medium
+
+  ** SNAPSHOT build @1e523033e4cf94509378a806d2ac9cf5dae38b76 **
+
+  * Adding better detection of encrypted DCPs by using avprobe to try and read the mxf files (still not 100% correct).
+  * UNRELEASED
+
+ -- Nimrod Adar <nimrod@nimrod.private>  Wed, 27 Aug 2014 15:37:46 +0300
+
+dcpman (0.1) UNRELEASED; urgency=medium
+
+  * Initial release.
+
+ -- Nimrod Adar <nimrod@shore.co.il>  Sun, 29 Jun 2014 16:19:53 +0300
+

fabfile.py

@@ -9,6 +9,7 @@ def publish ():
 
 @task
 def build ():
+    local ('''git dch -a''')
     local ('''dpkg-buildpackage''')
 
 @task