OTP migration task follow up

Deps

In OTP 19 /OTP 20 columns, please indicate:

• <branch with link> <status> <ci link>

Where:

• status: OK (compile with no warnings) | WARN (compile with warnings) | NO

dep	OTP 19	OTP 20	note
erlang_js	Ok	Ok	https://github.com/basho/erlang_js/pull/64
riak-erlang-client	Yes	Ok	https://github.com/basho/riak-erlang-client/pull/367
riak_pb	Ok	Ok	https://github.com/basho/riak_pb/pull/227
cuttlefish	-	Ok	https://github.com/basho/cuttlefish/pull/241
bitcask	-	Ok	https://github.com/basho/bitcask/tree/mcx/wip/otp20-compatibility