Use coredns/caddy to fix tests

[pvsune]

The tests fail:

$ go test ./...
# github.com/coredns/records [github.com/coredns/records.test]
./records_test.go:24:25: cannot use c (type *"github.com/caddyserver/caddy".Controller) as type *"github.com/coredns/caddy".Controller in argument to recordsParse
./records_test.go:83:25: cannot use c (type *"github.com/caddyserver/caddy".Controller) as type *"github.com/coredns/caddy".Controller in argument to recordsParse
./records_test.go:136:25: cannot use c (type *"github.com/caddyserver/caddy".Controller) as type *"github.com/coredns/caddy".Controller in argument to recordsParse
FAIL    github.com/coredns/records [build failed]
FAIL

Looks like there is inconsistency in using caddy in recordsParse(), use the stripped down coredns/caddy instead.