client: getting a non-existing client raises 500 instead of 404

[waynerobinson]

21:26:20 hydra.1    | time="2017-01-03T21:26:20+10:00" level=info msg="started handling request" method=GET remote="[::1]:63928" request="/clients/partner_ui_28"
21:26:20 hydra.1    | time="2017-01-03T21:26:20+10:00" level=error msg="An error occurred" error=": Not found" request_id=d3a57692-1ed6-40f3-aee7-8cc361838b59 status=500
21:26:20 hydra.1    | time="2017-01-03T21:26:20+10:00" level=debug msg="Stack trace: \ngithub.jparrowsec.cn/ory-am/hydra/client.(*SQLManager).GetConcreteClient\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/client/manager_sql.go:121\ngithub.jparrowsec.cn/ory-am/hydra/client.(*Handler).Get\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/client/handler.go:149\ngithub.jparrowsec.cn/ory-am/hydra/client.(*Handler).Get-fm\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/client/handler.go:35\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/julienschmidt/httprouter.(*Router).ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/julienschmidt/httprouter/router.go:299\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.Wrap.func1\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:41\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.HandlerFunc.ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:24\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.middleware.ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:33\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.(middleware).ServeHTTP-fm\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:33\nnet/http.HandlerFunc.ServeHTTP\n\t/usr/local/Cellar/go/1.6.2/libexec/src/net/http/server.go:1618\ngithub.jparrowsec.cn/ory-am/hydra/cmd/server.(*Handler).rejectInsecureRequests\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/cmd/server/handler.go:133\ngithub.jparrowsec.cn/ory-am/hydra/cmd/server.(*Handler).(github.com/ory-am/hydra/cmd/server.rejectInsecureRequests)-fm\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/cmd/server/handler.go:54\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.HandlerFunc.ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:24\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.middleware.ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:33\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.(middleware).ServeHTTP-fm\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:33\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/meatballhat/negroni-logrus.(*Middleware).ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/meatballhat/negroni-logrus/middleware.go:135\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.middleware.ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:33\ngithub.jparrowsec.cn/ory-am/hydra/vendor/github.com/urfave/negroni.(*Negroni).ServeHTTP\n\t/Users/waynerobinson/.go/src/github.com/ory-am/hydra/vendor/github.com/urfave/negroni/negroni.go:73\nnet/http.serverHandler.ServeHTTP\n\t/usr/local/Cellar/go/1.6.2/libexec/src/net/http/server.go:2081\nnet/http.(*conn).serve\n\t/usr/local/Cellar/go/1.6.2/libexec/src/net/http/server.go:1472\nruntime.goexit\n\t/usr/local/Cellar/go/1.6.2/libexec/src/runtime/asm_amd64.s:1998"