Remove duplicate osbs buildroot handling

We are handling this in the osbs cluster playbook, it's redundant
here.

Signed-off-by: Adam Miller <admiller@redhat.com>

roles/osbs-atomic-reactor/defaults/main.yml

@@ -28,4 +28,3 @@ atomic_reactor_git:
 
 atomic_reactor_rpm:
   copr: True
-  buildroot_cmd: atomic-reactor create-build-image --reactor-tarball-path /usr/share/atomic-reactor/atomic-reactor.tar.gz /usr/share/atomic-reactor/images/dockerhost-builder buildroot

roles/osbs-atomic-reactor/handlers/main.yml

@@ -1,3 +0,0 @@
----
-- name: rebuild buildroot
-  shell: "{{ atomic_reactor_rpm.buildroot_cmd }}"

roles/osbs-atomic-reactor/tasks/source_rpm.yml

@@ -1,5 +1,3 @@
 ---
 - name: install atomic-reactor package locally
   action: "{{ ansible_pkg_mgr }} name=atomic-reactor state=latest"
-  notify:
-    - rebuild buildroot