tests/testlib/obsmarker-common.sh

remotenames: rename related file and storage dir to logexchange

This patch renames remotenames.py to logexchange.py, test-remotenames.t to
test-logexchange.t. Also this patch renames the directory in which the data is
stored from remotenames to logexchange. After this patch, data about bookmarks
and branches from a server we pull is stored in
`.hg/logexchange/(bookmarks|branches)` files.

Thanks to smf for the suggestion.

Differential Revision: https://phab.mercurial-scm.org/D1607

mkcommit() {
   echo "$1" > "$1"
   hg add "$1"
   hg ci -m "$1"
}

getid() {
   hg log --hidden --template '{node}\n' --rev "$1"
}

cat >> $HGRCPATH <<EOF
[alias]
debugobsolete=debugobsolete -d '0 0'
EOF