Use Python 3 for tests

Signed-off-by: Simon McVittie <smcv@debian.org>

Closes: #1463
Approved by: cgwalters

ci/build.sh

@@ -16,7 +16,14 @@ pkg_install sudo which attr fuse strace \
 if test -n "${CI_PKGS:-}"; then
     pkg_install ${CI_PKGS}
 fi
-pkg_install_if_os fedora gjs gnome-desktop-testing parallel coccinelle clang
+pkg_install_if_os fedora gjs gnome-desktop-testing parallel coccinelle clang \
+                  python3-PyYAML
+(. /etc/os-release;
+ if test "${ID}" = "centos"; then
+     rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
+     pkg_install python34{,-PyYAML}
+ fi
+)
 
 # Default libcurl on by default in fedora unless libsoup is enabled
 if sh -c '. /etc/os-release; test "${ID}" = fedora'; then

ci/travis-install.sh

@@ -110,7 +110,7 @@ case "$ci_distro" in
             libcurl4-openssl-dev \
             procps \
             zlib1g-dev \
-            python-yaml \
+            python3-yaml \
             ${NULL}
 
         if [ "$ci_in_docker" = yes ]; then