Migrate to ubuntu1804-docker

Migrate the rest of the jobs from
ubuntu1604-docker to ubuntu1804-docker
Remove unused nodes

Issue-ID: CIMAN-373
Change-Id: Idec34497cec90f650336cdd2dcfc8aaae2bcd2ec
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
diff --git a/jjb/oom/offline-installer.yaml b/jjb/oom/offline-installer.yaml
index 29d9422..5e96e18 100644
--- a/jjb/oom/offline-installer.yaml
+++ b/jjb/oom/offline-installer.yaml
@@ -2,7 +2,7 @@
 - project:
     name: offline-installer
     project-name: 'offline-installer'
-    build-node: 'ubuntu1604-docker-8c-8g'
+    build-node: 'ubuntu1804-docker-8c-8g'
     offline_review_bootstrap: !include-raw-escape: offline-installer-review-bootstrap.sh
 
     stream: