This reverts commit 810417df86.
The Swift driver not being able to use Trusts had nothing to do
about the store driver itself nor that keystoneauth1 would have
broken the feature, but rather it not having the functionality
in the first place and us not catching that on reviews.
We should figure out how to test this before we try to replace
this code again.
Change-Id: If12a013404296486dc387b099477d1608b24ba63
Closes-Bug: #1916052
9b683678b2