Don't use find utility to find ebin directories.

Change-Id: I1375fc47e73d1c4a1449d4df88a99cb65c259f7b
Reviewed-on: http://review.couchbase.org/35007
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>