qt: Rely on the bad passphrase error reported by gpg
* lang/qt/src/qgpgmedecryptverifyjob.cpp (patch_decryption_result): Removed. (decrypt_verify): Remove usage of patch_decryption_result.
This reverts most of revision d8e5871dca9425811873058150677a158235613d.
- GnuPG-bug-id: T5939