Switch simple-init to support python3

Depending on the version of $DIB_PYTHON_VERSION, we can either use pip /
pip3 to install glean.  This is helpful for newer OSes that might not
want to ship python2 (pip).

Change-Id: I25c5927a1eb55ee16b919dd64403184f335839b6
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

diskimage_builder/elements/simple-init/install.d/simple-init-repo-install/40-glean

@@ -21,4 +21,8 @@ fi
 set -eu
 set -o pipefail
 
+if [ "$DIB_PYTHON_VERSION" == "3" ]; then
+    pip3 install /tmp/glean.git
+else
     pip install /tmp/glean.git
+fi

diskimage_builder/elements/simple-init/install.d/simple-init-source-install/40-glean

@@ -21,4 +21,8 @@ fi
 set -eu
 set -o pipefail
 
+if [ "$DIB_PYTHON_VERSION" == "3" ]; then
+    pip3 install glean
+else
     pip install glean
+fi