patchbomb: respect HGPLAIN when piping --test output to PAGER
It makes easy to use `hg email --test` from another tool.
#!/bin/sh
# test command parsing and dispatch
"$TESTDIR/hghave" no-outer-repo || exit 80
hg init a
cd a
echo a > a
hg ci -Ama
echo "# missing arg"
hg cat
echo '% [defaults]'
hg cat a
cat >> $HGRCPATH <<EOF
[defaults]
cat = -r null
EOF
hg cat a
echo '% no repo'
cd ..
hg cat
exit 0