shelve: make non bare shelve not saving branch information in bundle
This patch prepares for restoring newly created branch only on
bare shelve later because information about new-branch will be
preserved only when shelve was bare and working copy branch
was different than branch of its parent. In other case information
about new-branch will be gone, so unshelve will not recognise that
shelve was made on new-branch and it will not restore branch
information from the bundle to the working directory.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state