Align with namespace change in ESP8266 Arduino implementation of InterruptLock.

Author: dok-net

DHT.h

@@ -23,7 +23,6 @@
   #include <interrupts.h>
  #endif
 
-
 /* Uncomment to enable printing out nice debug messages. */
 //#define DHT_DEBUG
 
@@ -77,7 +76,9 @@ class DHT {
 
 };
 
-#if !defined(ESP8266)
+#if defined(ESP8266)
+using esp8266::InterruptLock;
+#else
 /*! 
  *  @brief  Class that defines Interrupt Lock Avaiability
  */