When setting up bearer(s) through F1, the corresponding F1 message has
QoS fields for the DRB(s) to be set up, as well as for all flows
associated to this DRB. In this commit, set the DRB QoS field to be
equal to the first flow (it is unclear/unspecified how it should be set
up, based on the flows), which was not set before and therefore
contained unitialized data.

The F1 module uses this data, and in split mode, F1 message generation
failed due to uninitialized data.