Fix decryption failure of publisher key and some bash syntax

[jmatsu]

Issue

• none but the motivation is in https://circleci.com/gh/DroidKaigi/conference-app-2018/1408

Overview (Required)

• The default cipher is sha256 since openssl v1.1 but only release publisher key was encrypted by md5.
• Therefore, we need to specify the appropriate cipher. to not only release publisher key just in case.

Links

• See openssl aes-256-cbc -k $KEYSTORE_DECRYPT_PASSWORD -d -in encrypted-droidkaigi-key -out release.keystore -md sha256 in https://circleci.com/gh/DroidKaigi/conference-app-2018/1412
• See openssl aes-256-cbc -k $PUBLISHER_KEYS_JSON_DECRYPT_PASSWORD -d -in encrypted-publisher-keys.json -out app/publisher-keys.json -md md5 in https://circleci.com/gh/DroidKaigi/conference-app-2018/1411

[jmatsu]

yay 💃

[takahirom]

🎉