Adding constraints support to libraries is slightly more complex than
services as the libraries themselves are listed in upper-constraints.txt
which leads to errors that you can't install a specific version and a
constrained version.
This change adds constraints support by also adding a helper script to
edit the constraints to remove oslo.messaging.
Change-Id: I8be883215f27abb58d15b85e8542cbdf32000bac
78f1137805