Fix default output url

[cehbrecht]

Overview

the default settings for outputurl would result in a broken url builded with urljoin in the storage module. This is fixed with this pull request.

Before:

urljoin('file:////tmp/T', 'output.txt') -> file://tmp/output.txt

Now:

urljoin('file:///tmp/T/', 'output.txt') -> file:///tmp/T/output.txt

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.
• [x ] I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[coveralls]

Coverage decreased (-0.03%) to 76.319% when pulling 990baa6 on bird-house:fix-default-output-url into 286296b on geopython:master.

[coveralls]

Coverage decreased (-0.03%) to 76.319% when pulling 990baa6 on bird-house:fix-default-output-url into 286296b on geopython:master.

[jachym]

Thanks @cehbrecht, as always