Make OS.get_locale() returns same value

platform/iphone/app_delegate.mm

@@ -401,8 +401,7 @@ static int frame_count = 0;
 			OSIPhone::get_singleton()->set_data_dir(
 					String::utf8([documentsDirectory UTF8String]));
 
-			NSString *locale_code =
-					[[[NSLocale preferredLanguages] objectAtIndex:0] substringToIndex:2];
+			NSString *locale_code = [[NSLocale currentLocale] localeIdentifier];
 			OSIPhone::get_singleton()->set_locale(
 					String::utf8([locale_code UTF8String]));
 

platform/osx/os_osx.mm

@@ -1228,8 +1228,8 @@ Error OS_OSX::shell_open(String p_uri) {
 }
 
 String OS_OSX::get_locale() const {
-	NSString *preferredLang = [[NSLocale preferredLanguages] objectAtIndex:0];
-	return [preferredLang UTF8String];
+	NSString *locale_code = [[NSLocale currentLocale] localeIdentifier];
+	return [locale_code UTF8String];
 }
 
 void OS_OSX::swap_buffers() {