Does not include jackson-core in the final artifacts

Given jackson-core is already provided by Gerrit, do not pack the
jackson-core artifact in the plugin jars.

Change-Id: I58513a1fa09e239acbb38ed2548090e8ab904f28
diff --git a/owners-common/common.bzl b/owners-common/common.bzl
index e9a7931..93c4871 100644
--- a/owners-common/common.bzl
+++ b/owners-common/common.bzl
@@ -1,5 +1,5 @@
-EXTERNAL_DEPS = [ 
-    '@jackson_core//jar',
+EXTERNAL_DEPS = [
+    '@jackson_core//jar:neverlink',
     '@jackson_databind//jar',
     '@jackson_annotations//jar',
     '@jackson_dataformat_yaml//jar'