histedit: don't clobber working copy on --abort if not on histedit cset
Similar to
issue4009, 2.7 will force people to abort histedits before
doing interesting things. Without this fix, people with histedit
sessions they wandered away from before upgrading to 2.7 could clobber
their working copy for no reason.
# invalid filenames
test-add.t
test-init.t
test-clone.t
test-contrib.t
test-hgweb-raw.t
test-walk.t
# no sockets or fifos
test-hup.t
test-inotify-debuginotify.t
test-inotify-dirty-dirstate.t
test-inotify-issue1208.t
test-inotify-issue1371.t
test-inotify-issue1542.t
test-inotify-lookup.t
test-inotify.t
test-inotify-issue1556.t
# no hardlinks
test-hardlinks.t
test-relink.t
# exec bit problems
test-convert-bzr-114.t
test-convert-bzr-directories.t
test-convert-bzr-merges.t
test-convert-bzr-treeroot.t
test-convert-darcs.t
test-merge-tools.t
# debugstate exec bit false positives
test-dirstate.t
test-filebranch.t
test-merge-remove.t