Remove default plan-environment.yaml

Left the one used for derive parameters that includes
the playbooks for derive parameters.

Depends-On: https://review.opendev.org/c/openstack/python-tripleoclient/+/777293
Change-Id: I7b82364bee7fcc3a89d36255b0c8507cdd1d5a38

plan-environment.yaml

@@ -1,8 +0,0 @@
-version: 1.0
-
-name: overcloud
-description: >
-  Default Deployment plan
-template: overcloud.yaml
-environments:
-  - path: overcloud-resource-registry-puppet.yaml

plan-samples/plan-environment-derived-params.yaml

@@ -1,11 +1,4 @@
 version: 1.0
-
-name: overcloud
-description: >
-  Default Deployment plan
-template: overcloud.yaml
-environments:
-  - path: overcloud-resource-registry-puppet.yaml
 playbook_parameters:
   cli-derive-parameters.yaml:
     ########### Role-Specific derive parameters ##############