When we started to commit the fuzzer QTest reproducers to
fuzz-test.c in commit d8dd1095 ("qtest: add fuzz test case"),
we forgot to add the corresponding MAINTAINERS entry. Do it now.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>