LACP update - 13: corrections in LACP outgoing PDU processing

Added corrections for outgoing LACP PDU s in LACP module. This #remove s #individual #TLV #serialization and solves #issue s with #buffer #allocation. PDU is serialized at once when it is sent out.

#LACP update 13 ...
[commit 85d0215162650e44e3932f3cc4e33d289f2250b7]