Replace all Ubuntu 16.04 with Ubuntu18.04 image
Change-Id: I86b84957145f7c1f253d3158e42e015c322788eb
diff --git a/jjb/verify/openolt-test.yaml b/jjb/verify/openolt-test.yaml
index c8ef753..67d0f99 100644
--- a/jjb/verify/openolt-test.yaml
+++ b/jjb/verify/openolt-test.yaml
@@ -16,7 +16,7 @@
- 'verify-licensed'
- 'tag-collision-reject'
- 'make-unit-test':
- build-node: 'ubuntu16.04-basebuild-2c-4g'
+ build-node: 'ubuntu18.04-basebuild-2c-4g'
build-timeout: 60
unit-test-targets: 'lint docker-build'
junit-allow-empty-results: true