[201811][submodule] Update swss and sai-redis submodules

[volodymyrsamotiy]

Signed-off-by: Volodymyr Samotiy volodymyrs@nvidia.com

- Why I did it
To add updated PFC storm detection logic for Mellanox platforms

- How I did it
Updated swss and sairedis submodes
depends on #6467

swss commits

• a1b6e5e [pfcwd] Update PFC storm detection logic for Mellanox platforms (Make Dell S6100 and Z9100 psuutil.py plugins compliant with Python 3.6 #1523)
• 4999565 [acl] Remove Ethertype from L3V6 qualifiers (Is sonic_sfp / sonic_psu (inherted by sfputil.py / psuutil.py) on the Porting Guilde re-designing?? #1433)

sairedis commits

• ae2c47f [SAI] Add PFC pause duration counters in microseconds ([submodule]: update sonic-platform-daemons submodule #731)

- How to verify it

1. Run all PFCWD tests from https://github.com/Azure/sonic-mgmt/tree/master/tests/pfcwd and verified all passed.
2. Manual test: manually start storm on fanout and manually put port down on fanout few times. Verified that no storm was detected when link was down

- Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[neethajohn]

retest broadcom please