[sub module] remove changes not ready yet (sonic-net#2662)

PFC_WD table naming change is not ready to be included yet.

Submodule src/sonic-swss-common c674e64..2592b0c (rewind):
  < Add multiple fields hdel support (sonic-net#267)
  < Update PFC_WD table name in CONFIG_DB (sonic-net#266)

Signed-off-by: Ying Xie <[email protected]>

Author: yxieca