Streamline nexus role tests by using smaller test images

A 140mb haproxy image was substituted with tiny alpine
image to make CI tests faster.

Change-Id: Ic1a234df8f293e12a6e864817a19bf5445f10fe9
Issue-ID: OOM-1942
Signed-off-by: Bartek Grzybowski <b.grzybowski@partner.samsung.com>
diff --git a/ansible/test/play-infrastructure/molecule/default/vars.yml b/ansible/test/play-infrastructure/molecule/default/vars.yml
index 6ca5a1a..8aa774b 100644
--- a/ansible/test/play-infrastructure/molecule/default/vars.yml
+++ b/ansible/test/play-infrastructure/molecule/default/vars.yml
@@ -18,7 +18,7 @@
     registry: "{{ molecule_test_registry }}"
     path: "/busybox"
     tag: "latest"
-  aaionap-haproxy:
+  alpine:
     registry: "{{ molecule_test_registry }}"
-    path: "/aaionap/haproxy"
-    tag: "1.2.4"
+    path: "/library/alpine"
+    tag: "latest"