tests/test-username-newline.t

revert: add support for reverting subrepos without --no-backup and/or --all

When a subrepo is reverted but --no-backup is not set, call revert on the
subrepo that is being reverted prior to updating it to the revision specified
in the parent repo's .hgsubstate file.

The --all flag is passed down to the subrepo when it is being reverted. If the
--all flag is not set, all files that are modified on the subrepo will be
reverted.

  $ 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
  abort: username 'foo\nbar2' contains a newline
  
  [255]
  $ hg ci -Am m -u "`(echo foo; echo bar3)`"
  transaction abort!
  rollback completed
  abort: username 'foo\nbar3' contains a newline!
  [255]