Add some verifications on db# and port when creating data adapter

src/main/java/in/nosd/redis/dataadapters/RedisLookupDataAdapter.java

@@ -237,20 +237,18 @@ public class RedisLookupDataAdapter extends LookupDataAdapter {
             return new AutoValue_RedisLookupDataAdapter_Config.Builder();
         }
 
- /*       @Override
+        @Override
         public Optional<Multimap<String, String>> validate() {
-        	final ArrayListMultimap<String, String> errors = ArrayListMultimap.create();
-
+            final ArrayListMultimap<String, String> errors = ArrayListMultimap.create();
             if (redisPort() < 1 || redisPort() > 65535) {
                 errors.put("redis_port", "Value cannot neither be smaller than 1 nor greater than 65535");
             }
             if (redisDB() < 0) {
                 errors.put("redis_database", "Value cannot be smaller than 0");
             }
-
             return errors.isEmpty() ? Optional.empty() : Optional.of(errors);
         }
-*/
+
         @AutoValue.Builder
         public abstract static class Builder {
             @JsonCreator