Add openSUSE Leap 15 gate-utils image

Change-Id: I6cd1f27e40d6328cd99b4d81cdfb495808578787
Co-Authored-By: Stephanie Miller <stephane@alum.mit.edu>

doc/source/gate-utils.rst

@@ -22,3 +22,13 @@ Alternatively, this step can be performed by running the script directly:
 .. code-block:: shell
 
   ./gate-utils/build.sh
+
+openSUSE Leap 15
+----------------
+
+To build an openSUSE leap 15 image, you can export varibles before
+running the build script:
+
+.. code-block:: shell
+
+   DISTRO=suse_15 ./gate-utils/build.sh

gate-utils/Dockerfile.suse_15

@@ -0,0 +1,5 @@
+ARG FROM=docker.io/opensuse/leap:15
+FROM ${FROM}
+LABEL maintainers=stephane@alum.mit.edu
+
+RUN zypper install -y ipcalc

zuul.d/gate-utils.yaml

@@ -17,9 +17,11 @@
     check:
       jobs:
         - openstack-helm-images-gate-utils-debian
+        - openstack-helm-images-gate-utils-suse_15
     gate:
       jobs:
         - openstack-helm-images-gate-utils-debian
+        - openstack-helm-images-gate-utils-suse_15
     #experimental:
     #  jobs:
     #    - openstack-helm-infra-five-ubuntu
@@ -42,3 +44,13 @@
       - ^zuul.d/gate-utils.yaml
     vars:
       distro: "debian"
+
+- job:
+    name: openstack-helm-images-gate-utils-suse_15
+    parent: openstack-helm-images-gate-utils
+    files:
+      - ^gate-utils/build.sh
+      - ^gate-utils/Dockerfile.suse_15$
+      - ^zuul.d/gate-utils.yaml
+    vars:
+      distro: "suse_15"