match: drop unnecessary removal of '.' from excluded roots
The repo root is nothing special when it comes to what directories to
visit: patterns like '-X relglob:*.py' should not exclude the top
directory, while '-X path:.' should (pointless as such a pattern may
be). The explicit removal of '.' from the set of excluded roots was
probably there to avoid removing the the root directory when any
patterns had been given, but since
20ad936ac5d2 (treemanifest: visit
directory 'foo' when given e.g. '-X foo/ba?', 2015-05-27), we only
exclude directories that should be completely excluded, so we no
longer need to special-case the root directory.
% creating repo
% add and commit
C test.py
% change
M test.py