virttest.qemu_vm: Add get_monitors_by_type() function

This function can be used to get monitors of the given type.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
qemu.tests.qmp_*: Use VM.get_monitory_by_type() function

Use VM.get_monitory_by_type() function to get QMP monitor(s).

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
qemu.tests.qmp_event_notification: Fix config main_monitor

The main monitor name is overriden to hmp1 and causes test failures...

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
qemu.tests.qmp_*: Pylint/style changes

No actual changes.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>