Fix regression causing loss of static system-information messages

In commit 8b1a2f8cd7a81c6b8c7cdb0963dcf89de7c46100 we started to
initialize bts->si_valid to 0.  This means we are skipping the manually
configured static system information.

Instead, we have to initialize bts->si_valid to bts->si_mode_static,
i.e. start with those that are static and not to be auto-generated.

Found while developing
http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo

Change-Id: Iab9cc93cf6d54560a72cc393cc3721a8d10e04bf
Closes: #2367
1 file changed