CBSP: on RESET, also clear the etws_timer, and stop ETWS PN broadcast

Normally, each ETWS CMD instructing to broadcast triggers a five second
etws_timer to send a zero-payload ETWS CMD that stops broadcasting, five
seconds later. Before this patch, this lingered past an ETWS RESET instruction.

Instead, clear the etws_timer on ETWS RESET, and make sure that all ETWS PN
broadcast is stopped by sending a zero payload ETWS CMD to the BTSes
immediately.

This will cause all CBSP ttcn3 tests to fail unless
Ifee313369a433a6a638c5fffdedee5363b8e47c2 is merged to osmo-ttcn3-hacks at the
same time.

Related: Ifee313369a433a6a638c5fffdedee5363b8e47c2 (osmo-ttcn3-hacks)
Change-Id: I925a041936c6163483d70fe6d158af368ec8c444
1 file changed