backout: correct commit status of no changes made (BC) (issue4190)
If backout generated no changes to commit, it showed wrong status, "changeset
<target> backs out changeset <target>", and raised TypeError with -v option.
This changes the return code to 1, which is the same as "hg commit" and
"hg rebase".
http://mercurial.selenic.com/bts/issue1438
$ "$TESTDIR/hghave" symlink || exit 80
$ hg init
$ ln -s foo link
$ hg add link
$ hg ci -mbad link
$ hg rm link
$ hg ci -mok
$ hg diff -g -r 0:1 > bad.patch
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --no-commit bad.patch
applying bad.patch
$ hg status
R link
? bad.patch