tests/test-abort-checkin.t

cmdutil: omit redundant "savecommitmessage()" in "tryimportone()"

The preceding patch causes that "makememctx()" with "editor" argument
saves (manually edited) commit message into ".hg/last-message.txt":
saving itself is executed indirectly in "memctx.__init__()".

This makes it redundant to invoke "savecommitmessage()" on caller side
of "makememctx()".

This patch omits such redundant "savecommitmessage()" invocation in
"tryimportone()".

"tryimportone()" uses one of "commiteditor" or "commitforceeditor" as
"editor" argument, and this causes saving commit message always.

  $ cat > abortcommit.py <<EOF
  > from mercurial import util
  > def hook(**args):
  >     raise util.Abort("no commits allowed")
  > def reposetup(ui, repo):
  >     repo.ui.setconfig("hooks", "pretxncommit.nocommits", hook)
  > EOF
  $ abspath=`pwd`/abortcommit.py

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ echo "abortcommit = $abspath" >> $HGRCPATH

  $ hg init foo
  $ cd foo
  $ echo foo > foo
  $ hg add foo

mq may keep a reference to the repository so __del__ will not be
called and .hg/journal.dirstate will not be deleted:

  $ hg ci -m foo
  error: pretxncommit.nocommits hook failed: no commits allowed
  transaction abort!
  rollback completed
  abort: no commits allowed
  [255]
  $ hg ci -m foo
  error: pretxncommit.nocommits hook failed: no commits allowed
  transaction abort!
  rollback completed
  abort: no commits allowed
  [255]

  $ cd ..