captcha-authentication: Use error() and errorDetails() when channel status change makes an operation fail
captcha-authentication: Use error() and errorDetails() when channel status change makes an operation fail

In case an operation fails with due to a channel status change, the error data in the interface
should already be filled. Given this case, expose CaptchaAuthentication's error instead of a new one.

detrout/telepathy-qt,anantkamath/telepathy-qt,TelepathyIM/telepathy-qt,freedesktop-unofficial-mirror/telepathy__telepathy-qt4,TelepathyQt/telepathy-qt,special/telepathy-qt-upstream,TelepathyIM/telepathy-qt,detrout/telepathy-qt,freedesktop-unofficial-mirror/telepathy__telepathy-qt4,tiagosh/telepathy-qt,anantkamath/telepathy-qt,detrout/telepathy-qt,TelepathyIM/telepathy-qt,TelepathyQt/telepathy-qt,tiagosh/telepathy-qt,TelepathyQt/telepathy-qt,freedesktop-unofficial-mirror/telepathy__telepathy-qt,TelepathyIM/telepathy-qt,TelepathyQt/telepathy-qt,special/telepathy-qt-upstream,freedesktop-unofficial-mirror/telepathy__telepathy-qt4,anantkamath/telepathy-qt,freedesktop-unofficial-mirror/telepathy__telepathy-qt,tiagosh/telepathy-qt,tiagosh/telepathy-qt,freedesktop-unofficial-mirror/telepathy__telepathy-qt,special/telepathy-qt-upstream,freedesktop-unofficial-mirror/telepathy__telepathy-qt4,freedesktop-unofficial-mirror/telepathy__telepathy-qt,TelepathyIM/telepathy-qt