enable the default constructor

Change-Id: I514dd86b3bcca916cc4c3479e0441e1e200c95f5
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/util.hpp b/util.hpp
index f2d68ea..73649f0 100644
--- a/util.hpp
+++ b/util.hpp
@@ -189,7 +189,7 @@
         int fd = -1;
 
     public:
-        Descriptor() = delete;
+        Descriptor() = default;
         Descriptor(const Descriptor&) = delete;
         Descriptor& operator=(const Descriptor&) = delete;
         Descriptor(Descriptor&&) = delete;