Use close_module_list() to free the list.

There are a pair of Coverity CIDs for these two.

src/add-ons/kernel/network/stack/device_interfaces.cpp

@@ -464,6 +464,8 @@ get_device_interface(const char* name, bool create)
 		}
 	}
 
+	close_module_list(cookie);
+
 	return NULL;
 }
 

src/add-ons/kernel/network/stack/stack.cpp

@@ -759,6 +759,8 @@ scan_modules(const char* path)
 			put_module(name);
 		}
 	}
+
+	close_module_list(cookie);
 }