drop libgsystem build-dependency

debian/changelog

@@ -5,6 +5,7 @@ ostree (2016.9-1) UNRELEASED; urgency=medium
     - update copyright file
     - update ostree-boot packaging: the utilities in /usr/sbin moved to
       /usr/lib/ostree
+    - drop libgsystem build-dependency
   * Explicitly build-depend on xsltproc, which is directly used
 
  -- Simon McVittie <smcv@debian.org>  Fri, 12 Aug 2016 10:30:01 +0100

debian/control

@@ -27,7 +27,6 @@ Build-Depends:
  libgirepository1.0-dev (>= 1.34.0),
  libglib2.0-dev (>= 2.40.0),
  libgpgme11-dev (>= 1.1.8),
- libgsystem-dev (>= 2015.1),
  liblzma-dev (>= 5.0.5),
  libmount-dev (>= 2.23),
  libselinux1-dev,
@@ -136,7 +135,6 @@ Depends:
  ca-certificates,
  cpio,
  fuse,
- gir1.2-gsystem-1.0,
  gir1.2-ostree-1.0,
  gjs,
  ostree,