Including upstream requirements

Now that internal OSM software does not specify python modules in
setup.py, we need to include the requirements.txt from the module
in the requirements-dev.in to generate the full list properly.

Change-Id: Iba7ef22a84371077f687b837d96d0397d72d7722
Signed-off-by: beierlm <mark.beierl@canonical.com>