event-test: Properly terminate strings printed from callbacks

event-test: Properly terminate strings printed from callbacks

Stdio was buffering strings in functions:
myDomainEventBlockJobCallback,
myDomainEventBlockThresholdCallback,
myDomainEventMemoryFailureCallback. It caused flushing the
printed strings from callbacks at the end of a run, not
gradually. The solution is to add \n at the end of each string.

Signed-off-by: Kristina Hanicova <khanicov@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>