MT#59962 DRedisConnection: no reply means something went wrong

Add a default case for `handle_redis_reply()`.
Fixes:

    Dereference after null check (FORWARD_NULL)
    4. var_deref_op: Dereferencing null pointer reply.

Change-Id: I22edbc3cb14f7e8662efe4c607e1502fbb8c56b6

apps/dsm/mods/mod_redis/DRedisConnection.cpp

@@ -99,7 +99,11 @@ int DRedisConnection::handle_redis_reply(redisReply *reply, const char* _cmd) {
       ERROR("REDIS Protocol error detected\n");
       disconnect();
       return DB_E_CONNECTION;
-    }    
+
+    default:
+      disconnect();
+      return DB_E_CONNECTION;
+    }
   }
 
   switch (reply->type) {