Fix NRE in IsSocketConnected()

Author: mythz

src/ServiceStack.Redis/PooledRedisClientManager.cs

@@ -646,7 +646,7 @@ public Dictionary<string, string> GetStats()
 
             var ret = new Dictionary<string, string>
             {
-                {"VersionString", "" + Text.Env.VersionString},
+                {"VersionString", "" + Env.VersionString},
 
                 {"writeClientsPoolSize", "" + writeClientsPoolSize},
                 {"writeClientsCreated", "" + writeClientsCreated},

src/ServiceStack.Redis/RedisNativeClient_Utils.cs

@@ -234,8 +234,10 @@ public bool HasConnected
 
         public bool IsSocketConnected()
         {
+            if (socket == null)
+                return false;
             var part1 = socket.Poll(1000, SelectMode.SelectRead);
-            var part2 = (socket.Available == 0);
+            var part2 = socket.Available == 0;
             return !(part1 & part2);
         }