[releng] Workaround pygobject build failure

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 124dd06889ff276b5c2f21b7499fe9a48de9c1d0
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed Feb 15 23:26:54 2017 -0600

    Workaround pygobject build failure

 tools/smoketesting/sample-tarball.jhbuildrc |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/tools/smoketesting/sample-tarball.jhbuildrc b/tools/smoketesting/sample-tarball.jhbuildrc
index 2d2c501..8992380 100644
--- a/tools/smoketesting/sample-tarball.jhbuildrc
+++ b/tools/smoketesting/sample-tarball.jhbuildrc
@@ -23,3 +23,6 @@ prefix = os.path.join(checkoutroot, 'install')
 # extra arguments to pass to all autogen.sh scripts
 # to speed up builds, try '--disable-static --disable-gtk-doc'
 autogenargs='--disable-static --disable-gtk-doc'
+
+# https://git.gnome.org/browse/pygobject/commit/?id=d005df9645fd5fb2f19bd09384355f45591f1e58
+module_autogenargs['pygobject'] = '--enable-compile-warnings=minimum'