lock_guard: remove explicit template

Change-Id: Iec6d57d6a66557a66096c7a8f67e025c6ca5a64c
diff --git a/src/upnp/protocol/pupnp/upnp_igd.h b/src/upnp/protocol/pupnp/upnp_igd.h
index 5ea7fe5..3324e80 100644
--- a/src/upnp/protocol/pupnp/upnp_igd.h
+++ b/src/upnp/protocol/pupnp/upnp_igd.h
@@ -48,37 +48,37 @@
 
     const std::string& getBaseURL() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return baseURL_;
     }
     const std::string& getFriendlyName() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return friendlyName_;
     }
     const std::string& getServiceType() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return serviceType_;
     }
     const std::string& getServiceId() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return serviceId_;
     }
     const std::string& getLocationURL() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return locationURL_;
     }
     const std::string& getControlURL() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return controlURL_;
     }
     const std::string& getEventSubURL() const
     {
-        std::lock_guard<std::mutex> lock(mutex_);
+        std::lock_guard lock(mutex_);
         return eventSubURL_;
     }