unixsocket: introduce a version/datacontrol header (2byte)

The ALT TC/Superchannel switch requires a seperate side channel. By introducing a header this
can be done in a clean way. So every packet gets
- 1 byte version
- 1 byte data or control

Change-Id: I0b601b67450b93291b2c2bcec5b0919050e18791
2 files changed