context: add a no-op _prestatus method
This patch adds a private _prestatus method so that certain contexts, such as
workingctx, can add custom pre-processing to status.
# this file holds the definitions that are used in various bzr tests
"$TESTDIR/hghave" bzr || exit 80
TERM=dumb; export TERM
echo '[extensions]' >> $HGRCPATH
echo 'convert = ' >> $HGRCPATH
glog()
{
hg log -G --template '{rev}@{branch} "{desc|firstline}" files: {files}\n' "$@"
}
manifest()
{
echo "% manifest of $2"
hg -R $1 manifest -v -r $2
}