Fix two logic issues in kis_assert_common

• kis_assert_recoverable should be recoverable, i.e., it shouldn't

call qFatal or throw an exception, so the isIgnorable parameter
should be true

• Because the button parameter was set to QMessageBox::Abort if

isIgnorable is false, the first condition would be true for all
non-recoverable asserts, which means that in practice, the exception
would never been thrown, because the button == QMessageBox::Abort
would always be true.