[snmpagent] update submodule

e54036c (HEAD, origin/master, origin/HEAD, master) [rfc1213] Interface MIB add l3 vlan interfaces & aggregate rif counters (sonic-net#169)
fd1eae7 Set swsscommon logging level (sonic-net#178)
706d504 Improve MockRedis _encode(): so it will work on all types of value (sonic-net#179)
64c93a1 [RFC4292][Namespace]: Fix implementation of RouteUpdater for multi-asic platform (sonic-net#176)
b8f19ee [sonic-snmpagent] SONiC physical entity mib extension (sonic-net#168)
6b94ec3 Replace swsssdk.SonicV2Connector with swsscommon.SonicV2Connector (SWIG wrapper of C++ implementation) in production code (sonic-net#162)

Signed-off-by: Stepan Blyshchak <stepanb@nvidia.com>