[cdc_stream] Fix issues found in tests (#40)

* [cdc_stream] Fix issues found in tests

Fixes a couple of issues found by integration testing:
- Unicode command line args in cdc_stream show up as question marks.
- Log is still named assets_stream_manager instead of cdc_stream.
- An error message contains stadia_assets_stream_manager_v3.exe.
- mount_dir was not the last arg as required by FUSE
- Promoted cache cleanup logs to INFO level since they're important
  for the proper workings of the system.
- Asset streaming cache dir is still %APPDATA%\GGP\asset_streaming.

* Address comments

cdc_stream/start_service_command.cc

@@ -116,7 +116,7 @@ absl::StatusOr<std::unique_ptr<Log>> StartServiceCommand::GetLogger() {
   }
 
   return std::make_unique<FileLog>(
-      level, GetLogPath(log_dir_.c_str(), "assets_stream_manager").c_str());
+      level, GetLogPath(log_dir_.c_str(), "cdc_stream").c_str());
 }
 
 // Runs the session management service and returns when it finishes.