for ConsulConfigurationSource if some errors happens in the reload process once, the initialized flag will keep false all the way, which will lead to the getConfiguration function throw IllegalStateException

[hqlvzs]

`public void reload() {
Map<String, String> newConsulValues = new HashMap<>();
List valueList;

try {
  LOG.debug("Reloading configuration from Consuls' K-V store");
  valueList = kvClient.getValues("/");
} catch (Exception e) {
  initialized = false;
  throw new SourceCommunicationException("Can't get values from k-v store", e);
}

for (Value value : valueList) {
  String val = "";

  if (value.getValueAsString().isPresent()) {
    val = value.getValueAsString().get();
  }

  LOG.trace("Consul provided configuration key: " + value.getKey() + " with value: " + val);

  newConsulValues.put(value.getKey(), val);
}

consulValues = newConsulValues;

}`

For this reload function, in my opinion, if no Exception has been caught, then we need to set the initialized as true

[Alexey Kanashevich]

fixed in #178
set true is incorrect. Retry and fail if not initialized much better. Please review