[Broadcom]: Update SAI to 3.1.3.4-20#2708

Merged

lguohan merged 1 commit intosonic-net:201803from

stcheng:201803_sai

Mar 27, 2019

Commits on Mar 26, 2019

[Broadcom]: Update SAI to 3.1.3.4-20
Shu0T1an ChenG
committed