graft: reuse the --log value passed initially in `hg graft --continue` (BC)
We now stores the value of --log flag passed initially in the graftstate and
reuse that value when doing `hg graft --continue` which is a nice behavior.
The test updates demonstrate the fix.
Since we now preserve the value by default, drop the mention of `--log` flag
from the hint which we see after conflicts.
Differential Revision: https://phab.mercurial-scm.org/D3662
#require docutils gettext
$ $TESTDIR/check-gendoc ru
checking for parse errors