Tweak the pipe test
Tweak the pipe test

Use tr instead of grep:
- avoid some nasty quoting
- it's easier to observe the effect of transformations

Signed-off-by: Jeremie Dimino <aa5d8c8bb73d4465608582ffc8dcd3cb76639f53@dimino.org>
Signed-off-by: Nathan Rebours <9d1531e67b3fd717aeb3bdeb8fe4128d946e28e7@gmail.com>

dra27/jbuilder,janestreet/jbuilder,janestreet/jbuilder,dra27/jbuilder,dra27/jbuilder,dra27/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder