tests: Rename qtests which have names ending "error"

tests: Rename qtests which have names ending "error"

We have three qtest tests which have test names ending with "error".
This is awkward because the output of verbose test runs looks like
  /crypto/task/error:                                                  OK
  /crypto/task/thread_error:                                           OK

which gives false positives if you are grepping build logs for
errors by looking for "error:". Since there are only three tests
with this problem, just rename them all to 'failure' instead.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1470307178-22848-1-git-send-email-peter.maydell@linaro.org