CBLT-229:  add 3rd param to build_cblite_ios.sh:  EDITION is 'community' or 'enterprise'

use:  ./build_cblite_ios.sh   branch_name  release_number   edition

Change-Id: I7b098e8fbaf2075e7ff1d1b18f637e734db6ba67
Reviewed-on: http://review.couchbase.org/35507
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>