cmdutil: minor refactoring of changeset_printer._show
- use ctx.branch() instead of directly accessing the extra field "branch"
- move definitions of locals ('extra' and 'branch') down to where they
are used
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH
hg init a
cd a
echo 'base' > base
hg ci -Ambase -d '1 0'
hg qnew -mmqbase mqbase
hg qsave
hg qrestore 2