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
$ hg init
$ touch a
$ unset HGUSER
$ echo "[ui]" >> .hg/hgrc
$ echo "username= foo" >> .hg/hgrc
$ echo " bar1" >> .hg/hgrc
$ hg ci -Am m
adding a
abort: username 'foo\nbar1' contains a newline
[255]
$ rm .hg/hgrc
$ HGUSER=`(echo foo; echo bar2)` hg ci -Am m
adding a
abort: username 'foo\nbar2' contains a newline
[255]
$ hg ci -Am m -u "`(echo foo; echo bar3)`"
adding a
transaction abort!
rollback completed
abort: username 'foo\nbar3' contains a newline!
[255]