remove old dependency for logrus

[szuecs]

We get build failures, because of your dependency

You should update github.com/Sirupsen/logrus to github.com/sirupsen/logrus

% make test
go test -v -race github.com/szuecs/external-dns github.com/szuecs/external-dns/controller github.com/szuecs/external-dns/endpoint github.com/szuecs/external-dns/internal/testutils  github.com/szuecs/external-dns/pkg/apis/externaldns github.com/szuecs/external-dns/pkg /apis/externaldns/validation github.com/szuecs/external-dns/plan github.com/szuecs/external- dns/provider github.com/szuecs/external-dns/registry github.com/szuecs/external-dns/source
../../kubernetes-incubator/external-dns/vendor/github.com/infobloxopen/infoblox-go-client/lock.go:5:2: case-insensitive import collision: "github.com/kubernetes-incubator/external-dns/vendor/github.com/Sirupsen/logrus" and "github.com/kubernetes-incubator/external-dns/vendor/github.com/sirupsen/logrus"
vendor/github.com/infobloxopen/infoblox-go-client/lock.go:5:2: case-insensitive import collision: "github.com/szuecs/external-dns/vendor/github.com/Sirupsen/logrus" and "github.com/szuecs/external-dns/vendor/github.com/sirupsen/logrus"
make: *** [test] Error 1