Do not explicitly download plugin-manager

Plugin-manager is included by default in the core Gerrit distribution
and does not need anymore to be downloaded from the CI.

Change-Id: I953e6b70f3fa43629ccfe8e320c99853b4cbc824
diff --git a/fpm/Makefile b/fpm/Makefile
index ca12b60..3309091 100644
--- a/fpm/Makefile
+++ b/fpm/Makefile
@@ -24,7 +24,6 @@
 LIBS_JOBS= \
   plugin-out-of-the-box-bazel-master-stable-3.0/lastSuccessfulBuild/artifact/bazel-genfiles/plugins/out-of-the-box/out-of-the-box.jar
 PLUGINS_JOBS= \
-  plugin-plugin-manager-bazel-master-stable-3.0/lastSuccessfulBuild/artifact/bazel-genfiles/plugins/plugin-manager/plugin-manager.jar \
   plugin-avatars-gravatar-bazel-master-stable-3.0/lastSuccessfulBuild/artifact/bazel-genfiles/plugins/avatars-gravatar/avatars-gravatar.jar \
   plugin-uploadvalidator-bazel-master-stable-3.0/lastSuccessfulBuild/artifact/bazel-genfiles/plugins/uploadvalidator/uploadvalidator.jar