consul client address configs are not parseable via go-socketaddr

[preetapan]

$docker run --name=dev-consul consul agent -dev -client='{{ GetInterfaceIP "eth0" }}'
==> Starting Consul agent...
==> Error creating agent: Invalid DNS bind address: Failed to parse IP: {{ GetInterfaceIP "eth0" }}

looks like we don't use the go-socketaddr library to parse this arg. We do for bind addr. This should be consistent for both.

[gwydirsam]

We ran into something similar --

==> WARNING: Expect Mode enabled, expecting 3 servers
==> Starting Consul agent...
==> Error creating agent: Invalid DNS bind address: Failed to parse IP: {{GetPrivateIP}}

The error checking here is being run before the templates are resolved here