Add search for rebar in the same directory

Change-Id: I73135be8d9a446bfd3da0ab1d6a12fa58613eea3
Reviewed-on: http://review.couchbase.org/35043
Tested-by: Trond Norbye <trond.norbye@gmail.com>
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>