Add patch from upstream fixing FTBFS on host machines without root= in /proc/cmdline

The reproducible builds armhf workers are one example.

debian/changelog

@@ -1,3 +1,11 @@
+ostree (2016.6-2) UNRELEASED; urgency=medium
+
+  * d/p/tests-Improve-check-for-proc-cmdline-kargs.patch: add patch from
+    upstream fixing FTBFS on host machines without root= in /proc/cmdline,
+    such as the reproducible builds armhf workers
+
+ -- Simon McVittie <smcv@debian.org>  Tue, 28 Jun 2016 09:26:01 +0100
+
 ostree (2016.6-1) unstable; urgency=medium
 
   [ Jeremy Bicha ]