Import commit from https://github.com/sisimai/p5-Sisimai/commit/fdbfe003542d1efff4221b4e3aa7bb9df76f95a2: Fix code to decode a Subject header of the original message
Import commit from https://github.com/sisimai/p5-Sisimai/commit/fdbfe003542d1efff4221b4e3aa7bb9df76f95a2: Fix code to decode a Subject header of the original message

azumakuniyuki/rb-Sisimai,azumakuniyuki/rb-Sisimai