Fix prechecks fail with docker not in deployment host

This changes only evaluates baremetal host group
to look for docker versions.

Change-Id: I64a7314b332958d003f88a00aa73ba79a760a051
Closes-Bug: #1700986

ansible/roles/prechecks/tasks/package_checks.yml

@@ -3,6 +3,7 @@
   command: "{{ ansible_python.executable }} -c \"import docker; print docker.__version__\""
   register: result
   changed_when: false
+  when: inventory_hostname in groups['baremetal']
   failed_when: result | failed or
                result.stdout | version_compare(docker_py_version_min, '<')
 

ansible/roles/prechecks/tasks/service_checks.yml

@@ -3,6 +3,7 @@
   command: docker version
   register: result
   changed_when: false
+  when: inventory_hostname in groups['baremetal']
   failed_when: result | failed
                or (result.stdout | from_yaml).Server.Version | regex_replace('(\\d+\\.\\d+\\.\\d+).*', '\\1') | version_compare(docker_version_min, '<')