copr: be: drop mock config leftovers by provision_config

We can not simply use delete=yes on all provision files, because some of
those are created from templates.  So only pick subdirectory which is
safe to delete=yes.  This should resolve copr issue
https://pagure.io/copr/copr/issue/1104

roles/copr/backend/tasks/main.yml

@@ -169,6 +169,12 @@
   tags:
   - provision_config
 
+- name: "put provisioning files [remove mock config leftovers]"
+  synchronize: src="provision/files/mock/" dest="/home/copr/provision/files/mock/"
+               delete=yes
+  tags:
+  - provision_config
+
 - name: put some files into the provision subdir
   template:
     src: "provision/{{ item }}"