gnu: python2-dogtail: Update to 0.9.11.

There are newer releases on a gitlab.com repository compared to PyPI. Make an
attempt at getting the tests to work, they don't yet I believe because DBus
isn't working properly. This update is a step towards getting a Python 3
variant of the package, which can be used to test virt-manager.

* gnu/packages/python-xyz.scm (python2-dogtail): Update to 0.9.11.
[source]: Switch from PyPI to gitlab.com, as gitlab.com contains newer
releases.
[arguments]: Replace the check phase, and update comment about disabling the
tests.
[propagated-inputs,native-inputs]: Add relevant packages.
[home-page]: Change to https://gitlab.com/dogtail/dogtail/