This was done to avoid integrity issues, when the UE's RRC erroneously sent
measurement reports while the re-establishment was already in progress.
As errously sending PDCP PDUs on DRBs can cause issues as well, this was
disabled too.
this patch mainly modernizes the bearer creation to use smart pointers.
that allows to simplify the error handling.
ue_stack is changed to match new interface. This commit compiles
but doesn't work.
we had it returning int but had a bug in using the return value properly,
i.e. handling when -1 was returned in RLC TM.
Thinking about it more, it doesn't make sense to have a negative return
value here anyway. Either the RLC can return a PDU or not. If it can't the
returned lenght is zero.