CI: Use Python 3

The dbus-1.12 branch needed Python, which the master branch no longer
does, but we can at least use a modern Python.

Signed-off-by: Simon McVittie <smcv@collabora.com>

tools/ci-build.sh

@@ -111,7 +111,7 @@ case "$ci_buildsys" in
         # to assert that our official release tarballs will be enough
         # to build with CMake.
         mkdir -p ci-build-dist
-        ( cd ci-build-dist; ../configure )
+        ( cd ci-build-dist; ../configure PYTHON=python3 )
         make -C ci-build-dist dist
         tar -zxvf ci-build-dist/dbus-1.*.tar.gz
         cd dbus-1.*/
@@ -256,6 +256,7 @@ case "$ci_buildsys" in
             --enable-installed-tests \
             --enable-maintainer-mode \
             --enable-modular-tests \
+            PYTHON=python3 \
             "$@"
 
         ${make}

tools/ci-install.sh

@@ -177,9 +177,9 @@ case "$ci_distro" in
             libselinux1-dev
             libsystemd-dev
             libx11-dev
-            python
-            python-dbus
-            python-gi
+            python3
+            python3-dbus
+            python3-gi
             sudo
             valgrind
             wget