fix_snmp hard-coded community "public" and found the management VLAN
for the source interface with a substring match, so 10.0.0.1 matched
10.0.0.10 and a DNS name never matched (#3).
The driver implements napalm-device-types 4.13's configure_snmp_agent
steps: the caller's community (read-only, viewDefault), the source
interface set to the VLAN whose address is exactly the listen address
or the management address, configuration saved, and the community
checked in show snmp community. Contact and location are reported as
not set; there is no verified CLI for them on this switch. A value
that would break the CLI is refused.
The requirements now name napalm-device-types 4.13 in both files.
BREAKING CHANGE: run_device_action is removed.
Part of #3 and #4.
