As of recently, we failed to correctly discover repositories at a
Win32 system root. Instead of aborting the upwards-traversal of
the file system, we were looping infinitely when traversal
started at either a Win32 drive prefix ("C:/") or a network path
("//somehost").
The issue has been fixed, so add a test to catch regressions.
The constructor to git_repository is now called
'git_repository_open(path)'
and takes a path to a git repository instead of an existing ODB object.
Unit tests have been updated accordingly and the two test repositories
have been merged into one.
Signed-off-by: Vicent Marti <tanoku@gmail.com>