tests/narrow-library.sh

persistent-nodemap: drop the storage.revlog.nodemap.mode config

We now have a new, better, higher level, option. So we can drop the older one as
planned.

Differential Revision: https://phab.mercurial-scm.org/D9763

cat >> $HGRCPATH <<EOF
[extensions]
narrow=
[ui]
ssh=$PYTHON "$RUNTESTDIR/dummyssh"
[experimental]
changegroup3 = True
EOF