remove 1.5 clusterctl tests

Change-Id: I125e431e44abd706a8fe8253de1e788975c67d17
diff --git a/jjb/metal3/projects.yml b/jjb/metal3/projects.yml
index acc8267..f36ca6b 100644
--- a/jjb/metal3/projects.yml
+++ b/jjb/metal3/projects.yml
@@ -319,9 +319,6 @@
         - release-1-6:
             capm3_release_branch: release-1.6
             bmo_release_branch: release-0.5
-        - release-1-5:
-            capm3_release_branch: release-1.5
-            bmo_release_branch: release-0.4
         exclude:
         - image_os: centos
     - capm3_e2e_k8s_upgrade_tests_prow:
@@ -370,10 +367,6 @@
             capm3_release_branch: release-1.6
             bmo_release_branch: release-0.5
             schedule: "H 22 * * 2"
-        - release-1-5:
-            capm3_release_branch: release-1.5
-            bmo_release_branch: release-0.4
-            schedule: "H 22 * * 4"
         exclude:
         - image_os: centos
     - capm3_periodic_e2e_k8s_upgrade_tests_prow: