Stacktrace completo:

➜  ~ pip install virtualenv
Traceback (most recent call last):
  File "/usr/bin/pip", line 11, in <module>
    sys.exit(main())
  File "/usr/lib/python3.4/site-packages/pip/__init__.py", line 215, in main
    locale.setlocale(locale.LC_ALL, '')
  File "/usr/lib64/python3.4/locale.py", line 592, in setlocale
    return _setlocale(category, locale)
locale.Error: unsupported locale setting

No mesmo servidor, eu corri com sucessopip install virtualenv com python 2.7.x.

Agora, eu acabei de instalar o python3.4 usandocurl https://bootstrap.pypa.io/get-pip.py | python3.4.

➜  ~ pip --version
pip 8.1.1 from /usr/lib/python3.4/site-packages (python 3.4)

pip uninstall virtualenv também lança o mesmo erro