Convert system/tools/sysprop to Result::ok()

No functionality changes, this is a mechanical cleanup.

Test: cd system/apexd && m
Change-Id: I5da354e48d0fb12721dd430a6e9ad2d83b040a5e
diff --git a/JavaMain.cpp b/JavaMain.cpp
index 723e2d3..370b00e 100644
--- a/JavaMain.cpp
+++ b/JavaMain.cpp
@@ -93,14 +93,14 @@
 int main(int argc, char* argv[]) {
   Arguments args;
   std::string err;
-  if (auto res = ParseArgs(argc, argv, &args); !res) {
+  if (auto res = ParseArgs(argc, argv, &args); !res.ok()) {
     LOG(ERROR) << res.error();
     PrintUsage(argv[0]);
   }
 
   if (auto res = GenerateJavaLibrary(args.input_file_path, args.scope,
                                      args.java_output_dir);
-      !res) {
+      !res.ok()) {
     LOG(FATAL) << "Error during generating java sysprop from "
                << args.input_file_path << ": " << res.error();
   }