[submodule update] sonic-snmpagent

a4f39ac580cdc4bc816b829adefa56626332b6d6 (HEAD -> 201911, origin/201911) [RouteUpdater]: Fix multi_asic mock function implementation and multi_asic variable name (#186)
583265e521df440549d29fd2ef403c09f9e907ab [LLDP]: Update init_db to load global database config (#166)
005cf2e14005220699b57b0165b00914d009a852 Fix: correctly handle that lldp_loc_man_addr contains only IPv6 address without IPv4 address (#164)

Signed-off-by: Abhishek Dosi <abdosi@microsoft.com>