Skip test based on missing line type

Instead of explicit server version checking. Ubuntu installed version
string is not parsable by go-version. e.g.

10.2 (Ubuntu 10.2-1.pgdg16.04+1)

pgtype/line_test.go

@@ -3,23 +3,14 @@ package pgtype_test
 import (
 	"testing"
 
-	version "github.com/hashicorp/go-version"
 	"github.com/jackc/pgx/pgtype"
 	"github.com/jackc/pgx/pgtype/testutil"
 )
 
 func TestLineTranscode(t *testing.T) {
 	conn := testutil.MustConnectPgx(t)
-	serverVersion, err := version.NewVersion(conn.RuntimeParams["server_version"])
-	if err != nil {
-		t.Fatalf("cannot get server version: %v", err)
-	}
-	testutil.MustClose(t, conn)
-
-	minVersion := version.Must(version.NewVersion("9.4"))
-
-	if serverVersion.LessThan(minVersion) {
-		t.Skipf("Skipping line test for server version %v", serverVersion)
+	if _, ok := conn.ConnInfo.DataTypeForName("line"); !ok {
+		t.Skip("Skipping due to no line type")
 	}
 
 	testutil.TestSuccessfulTranscode(t, "line", []interface{}{