lint: Implicitly using the default locale is a common source of bugs: Use toUpperCase(Locale) instead

[n8fr8]

Wrote HTML report to file:///builds/guardianproject/orbot/orbotservice/build/reports/lint-results-debug.html
Lint found 1 error and 99 warnings. First failure:
/builds/guardianproject/orbot/orbotservice/src/main/java/org/torproject/android/service/OrbotRawEventListener.java:113: Error: Implicitly using the default locale is a common source of bugs: Use toUpperCase(Locale) instead. For strings meant to be internal use Locale.ROOT, otherwise Locale.getDefault(). [DefaultLocale]
String countryCode = mService.conn.getInfo("ip-to-country/" + node.ipAddress).toUpperCase();