Fail correctly in go-to-protobuf

We need to return earlier.

cmd/libs/go2idl/go-to-protobuf/protobuf/cmd.go

@@ -179,13 +179,13 @@ func Run(g *Generator) {
 		},
 		"public",
 	)
-	c.Verify = g.Common.VerifyOnly
-	c.FileTypes["protoidl"] = NewProtoFile()
-
 	if err != nil {
 		log.Fatalf("Failed making a context: %v", err)
 	}
 
+	c.Verify = g.Common.VerifyOnly
+	c.FileTypes["protoidl"] = NewProtoFile()
+
 	if err := protobufNames.AssignTypesToPackages(c); err != nil {
 		log.Fatalf("Failed to identify Common types: %v", err)
 	}