[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 (#267)
  < Update PFC_WD table name in CONFIG_DB (#266)

Signed-off-by: Ying Xie <ying.xie@microsoft.com>