We now use PCUIF v11 in the TTCN3 tests exclusively and also osmo-bts
and osmo-bsc only support PCUIF v11. There is no longer a need to
maintain a backward compatibility to PCUIF v10 in osmo-pcu.
Related: OS#5927
Change-Id: I68a3f59d5c960ae3a4fbd74f9d4a894295cb9ed8