tests/narrow-library.sh

errors: format "abort: " text in a new Abort.format() method

This remove some duplication we had.

Differential Revision: https://phab.mercurial-scm.org/D9348

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