New upstream release.

debian/changelog

@@ -1,3 +1,9 @@
+dulwich (0.17.3-1) UNRELEASED; urgency=medium
+
+  * New upstream release.
+
+ -- Jelmer Vernooij <jelmer@debian.org>  Sun, 18 Jun 2017 19:39:41 +0000
+
 dulwich (0.17.1-1) experimental; urgency=medium
 
   * Remove -dbg packages and migrate to -dbgsym packages.