Allow osmo-bsc sending a Deact SACCH messages in most cases. Prepare the
ttcn3-bsc-tests to not break just because of those messages that will soon be
sent.
When releasing an lchan, it makes sense to Deactivate SACCH on it, if it was
ever active. So far osmo-bsc was fairly reluctant to send Deactivate SACCH, but
osmo-bsc Id3301df059582da2377ef82feae554e94fa42035 is about to change that.
In most test cases, Deact SACCH are still optional, but in one case, the
current missing Deact SACCH will introduce a test failure: in the 'interleave'
of BSC_Tests.TC_ho_out_fail_no_ho_detect.
As soon as abovementioned osmo-bsc patch is merged, the test will pass again.
Also, as soon as Ibc64058f1e214bea585f4e8dcb66f3df8ead3845 is merged here, the
bsc tests will properly ensure whether Deact SACCH is sent or not in all tests.
Change-Id: I27da24dbe3184fa7a076a35f6fa6af457c1db8d2
861a4c174c