Allow Falcon versions <0.2.0

Falcon 0.1.7 includes a bug fix wrt accept header parsing, that is needed
by Marconi.

I would like to allow future releases in the 0.1.x series in order to pick
up bug fixes like this without having to update global reqs each time.

Change-Id: I8352e406a1f7b28a53b3aef6c8b9b99f86120d55
Partial-Bug: #1261904
Merge "Allow Falcon versions <0.2.0"