You are using pip version 8.1.2, however version 9.0.1 is available.

[root@localhost ~]# pip install virtualenvmapper
Collecting virtualenvmapper
  Could not find a version that satisfies the requirement virtualenvmapper (from versions: )
No matching distribution found for virtualenvmapper
You are using pip version 8.1.2, however version 9.0.1 is available.
You should consider upgrading via the ‘pip install --upgrade pip‘ command.

zhixing  :pip install --upgrade pip