Travis CI: actually return non-zero exit status when the test job fails

The original code did not actually propagate the test runner exit status
to parent process so Travis CI job was always green.

Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>

.travis_run_task.sh

@@ -47,7 +47,11 @@ ipa-docker-test-runner -l $CI_RESULTS_LOG \
     --git-repo $TRAVIS_BUILD_DIR \
     $TASK_TO_RUN $test_set
 
-if $?
+exit_status="$?"
+
+if [[ "$exit_status" -ne 0 ]]
 then
     truncate_log_to_test_failures
 fi
+
+exit $exit_status