Various fixes to Services Kit

* Remove useless dummy protocol loop in UrlRequest
 * Stop HTTP requests before deleting the socket and other things the
loop may still be using
 * Deletion of items from the authentication map wasn't working
 * Remove some debug traces

headers/os/net/UrlRequest.h

@@ -47,7 +47,7 @@ public:
 
 protected:
 	static	int32					_ThreadEntry(void* arg);
-	virtual	status_t				_ProtocolLoop();
+	virtual	status_t				_ProtocolLoop() = 0;
 	virtual void					_EmitDebug(BUrlProtocolDebugMessage type,
 										const char* format, ...);
 protected: