shelve: let cmdutil.revert() take care of backing up untracked files
cmdutil.revert() backs up untracked files, so I don't see a reason to
do it shelve.mergefiles(). We have tests for this and they still pass.
Differential Revision: https://phab.mercurial-scm.org/D6174
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.