c70525bb84 broke Python 2.6 compatibility
by using a dict comprehension, which is a Python 2.7 feature. I replaced
it with calling dict with a generator expression, which looks almost as
good and it works in Python 2.6.
https://github.com/pypa/pip/issues/1867
When hash randomization is enabled, pip can return different names for
git editables from run to run.
This change accounts for that in the tests for freezed output.