fix #447

[huard]

Overview

Fixes #447

Contribution Agreement

(as per https://github.com/geopython/pywps/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to PyWPS. I confirm that my contributions to PyWPS will be compatible with the PyWPS license guidelines at the time of contribution.
• I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[cehbrecht]

@huard not checked yet if it works on my side. But travis complains about pep8.

[cehbrecht]

tested locally with emu and it works :)

[cehbrecht]

@huard thanks :)