Merge pull request #71 from bjornorri/fix-country-code-crash

Avoid crash when country code is nil

RNDeviceInfo/RNDeviceInfo.m

@@ -163,7 +163,7 @@ RCT_EXPORT_MODULE()
              @"deviceId": self.deviceId,
              @"deviceName": currentDevice.name,
              @"deviceLocale": self.deviceLocale,
-             @"deviceCountry": self.deviceCountry,
+             @"deviceCountry": self.deviceCountry ?: [NSNull null],
              @"uniqueId": uniqueId,
              @"bundleId": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleIdentifier"],
              @"appVersion": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"],