build-sys: Post-release version bump

Closes: #1387
Approved by: jlebon

configure.ac

@@ -4,10 +4,10 @@ dnl update libostree-released.sym from libostree-devel.sym, and update the check
 dnl in test-symbols.sh, and also set is_release_build=yes below.  Then make
 dnl another post-release commit to bump the version, and set is_release_build=no.
 m4_define([year_version], [2017])
-m4_define([release_version], [15])
+m4_define([release_version], [16])
 m4_define([package_version], [year_version.release_version])
 AC_INIT([libostree], [package_version], [walters@verbum.org])
-is_release_build=yes
+is_release_build=no
 AC_CONFIG_HEADER([config.h])
 AC_CONFIG_MACRO_DIR([buildutil])
 AC_CONFIG_AUX_DIR([build-aux])