Add python-savannaclient to requirements

Savanna client CLI tests was already merged w/o adding
python-savannaclient to requirements:
I67d3d1e6f72e5c4e07cdb26743d020cb1e91a434

Change-Id: Ia3c1a7413e2f127489b641b4eaaa91cca7e7b18a
Closes-Bug: #1281954
Merge "Add python-savannaclient to requirements"