improve crnti reception (still not correct, we need to reconfigure the UE)

TODO: if the UE did random access (followed by a MAC uplink with
CRNTI) because none of its scheduling request was granted, then
according to 36.321 5.4.4 the UE's MAC will notify RRC to release
PUCCH/SRS. According to 36.331 5.3.13 the UE will then apply
default configuration for CQI reporting and scheduling requests,
which basically means that the CQI requests won't work anymore and
that the UE won't do any scheduling request anymore as long as the
eNB doesn't reconfigure the UE.
We have to take care of this. As the code is, nothing is done and
the UE state in the eNB is wrong.