* lang/qt/src/debug.cpp (operator<<): Use Error::asStdString instead of
Error::asString.
* lang/qt/src/qgpgmedecryptverifyjob.cpp (decrypt_verify),
lang/qt/src/qgpgmenewcryptoconfig.cpp
(QGpgMENewCryptoConfigComponent::sync),
lang/qt/src/qgpgmewkdlookupjob.cpp (startDirmngr): Use QDebug operator
for Error instead of Error::asString.
* lang/qt/src/threadedjobmixin.cpp (_detail::audit_log_as_html): Use
errorAsString instead of Error::asString.
* lang/qt/src/util.h (errorAsString): New.
* lang/qt/tests/run-decryptverifyarchivejob.cpp (main),
lang/qt/tests/run-decryptverifyjob.cpp (main),
lang/qt/tests/run-encryptarchivejob.cpp (main),
lang/qt/tests/run-encryptjob.cpp (main),
lang/qt/tests/run-exportjob.cpp (main),
lang/qt/tests/run-importjob.cpp (main),
lang/qt/tests/run-receivekeysjob.cpp (main),
lang/qt/tests/run-refreshkeysjob.cpp (main),
lang/qt/tests/run-signarchivejob.cpp (main),
lang/qt/tests/run-signjob.cpp (main),
lang/qt/tests/run-verifydetachedjob.cpp (main),
lang/qt/tests/run-verifyopaquejob.cpp (main),
lang/qt/tests/run-wkdrefreshjob.cpp (main),
lang/qt/tests/t-ownertrust.cpp (testChangeOwnerTrust),
lang/qt/tests/t-remarks.cpp (testRemarkOwnKey),
lang/qt/tests/t-tofuinfo.cpp (testTofuPolicy): Use QDebug operator for
Error instead of Error::asString.
* lang/qt/tests/t-changeexpiryjob.cpp (all test functions),
lang/qt/tests/t-trustsignatures.cpp (all test functions),
lang/qt/tests/t-various.cpp (testSignKeyWithoutExpiration,
testSignKeyWithExpiration): Use errorAsString instead of
Error::asString.