BTS: manually compose Rest Octets for SI Type 3 and 4

Finally, we can get rid of hard-coded octetstrings and control
every field of the Rest Octets we're sending to the IUT.

Note that template 'ts_SI4_default' did not contain any Rest
Octets at all, thus the GPRS indicator was (and still is)
absent. This will be fixed in a follow up change.

Change-Id: I0a95b34b495267edf1f48692e24fcd5ede8ccdd1
Signed-off-by: Vadim Yanitskiy <axilirator@gmail.com>
3 files changed