vty: add cmd subscriber ID sms delete-all

In ttcn3-msc-tests, so far we leave an intentionally failed MT SMS in the SMS
queue, which may cause it to re-appear in subsequent tests.

Allow removing all SMS for a given subscriber from the SMS database for good.

(I dimly remember a user report where the SMS queue spams failed SMS attempts,
and the only way to get rid of SMS for a given subscriber is to tamper with the
sms.db file directly. This should no longer be necessary with this command.)

Related: I7dce12942a65eaaf97f78ca69401c7f93faacb9e (osmo-ttcn3-hacks)
Change-Id: I637cbd7adc075a192f49752b38779391472ff06d
1 file changed