Fix subprocess.check_output invocation
Fix subprocess.check_output invocation

% python -c "import subprocess; subprocess.check_output('pyenv help')"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 216, in check_output
    process = Popen(stdout=PIPE, *popenargs, **kwargs)
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 394, in __init__
    errread, errwrite)
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1047, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

% python -c "import subprocess; subprocess.check_output(['pyenv','help'])"

pjz/Zappa,Miserlou/Zappa,Miserlou/Zappa,pjz/Zappa