Remove build for master-branch of imagare

The imagare plugin is now deprecated.

Change-Id: I20c031e8b78bf2c9c2a4b8599cceddbe4aa21213
diff --git a/jenkins/gerrit-bazel-plugin-imagare.yaml b/jenkins/gerrit-bazel-plugin-imagare.yaml
index 6b0cd9b..e5a0c32 100644
--- a/jenkins/gerrit-bazel-plugin-imagare.yaml
+++ b/jenkins/gerrit-bazel-plugin-imagare.yaml
@@ -3,6 +3,5 @@
     jobs:
       - 'plugin-{name}-bazel-{branch}':
           branch:
-            - master
             - stable-3.2
             - stable-2.16