[pygobject] ci: work around pip3 install --user not working in recent fdo-sdk

[Christoph Reiter <creiter src gnome org>]

commit 6376c11c0f93e35a222d29d654651c1b4cf0c384
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Fri May 17 16:06:05 2019 +0200

    ci: work around pip3 install --user not working in recent fdo-sdk
    
    https://gitlab.com/freedesktop-sdk/freedesktop-sdk/issues/776

 .gitlab-ci/test-flatpak.sh | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/.gitlab-ci/test-flatpak.sh b/.gitlab-ci/test-flatpak.sh
index 3ca5a746..0dd01c46 100755
--- a/.gitlab-ci/test-flatpak.sh
+++ b/.gitlab-ci/test-flatpak.sh
@@ -2,5 +2,8 @@
 
 set -e
 
+python3 -m pip install --user pytest pytest-faulthandler
+# for some reason pip3 fails the first time now..
+# https://gitlab.com/freedesktop-sdk/freedesktop-sdk/issues/776
 python3 -m pip install --user pytest pytest-faulthandler
 python3 setup.py test -s