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: I1b9660bb3e6d22eb199757f6c90e4fdeef0c707c
Signed-off-by: beierlm <mark.beierl@canonical.com>