check docker version

[pengdake]

when I run the command to precheck environment,I get error from "Checking Docker version".
           ^"}

[root@hosts tasks]# docker version
Client:
 Version: 17.12.0-ce
 API version: 1.35
 Go version: go1.9.2
 Git commit: c97c6d6
 Built: Wed Dec 27 20:10:14 2017
 OS/Arch: linux/amd64

Server:
 Engine:
  Version: 17.12.0-ce
  API version: 1.35 (minimum version 1.12)
  Go version: go1.9.2
  Git commit: c97c6d6
  Built: Wed Dec 27 20:12:46 2017
  OS/Arch: linux/amd64
  Experimental: false

TASK [prechecks : Checking Docker version] *********************************************************************************
fatal: [localhost]: FAILED! => {"msg": "The conditional check 'result | failed or (result.stdout | from_yaml).Server.Version | regex_replace('(\\\\d+\\\\.\\\\d+\\\\.\\\\d+).*', '\\\\1') | version_compare(docker_version_min, '<')' failed. The error was: while scanning for the next token\nfound character '\\t' that cannot start any token\n in \"<unicode string>\", line 2, column 10:\n Version:\t17.12.0-ce\n

[OpenStack Infra (hudson-openstack)]

Change abandoned by Qi Peng (<email address hidden>) on branch: master
Review: https://review.openstack.org/533697