upgrade: support the --quiet flag
The command is currently very verbose with a various bit of output being time
sensitive or randomized. The make invocation bulky and hard to match in the
test. We move various message from `ui.write` to `ui.status` in order for the
`--quiet` flag to have effect and helps the situation.
As a side benefit, we can replace the various redirection to > /dev/null with the --quiet flag.
Differential Revision: https://phab.mercurial-scm.org/D8429
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.