Fix comment typo

Author: durran

lib/mongo/retryable.rb

@@ -50,7 +50,7 @@ def read_with_retry(attempt = 0, &block)
         if cluster.sharded? && e.retryable?
           if attempt < max_read_retries
             # We don't scan the cluster in this case as Mongos always returns
-            # ready after a ping whether no matter what the state behind it is.
+            # ready after a ping no matter what the state behind it is.
             sleep(read_retry_interval)
             read_with_retry(attempt - 1, &block)
           end