vlan: implement delete interface

Delete the in-memory vlan object,Also
deletes the associated device file and the
network file.

Change-Id: I613e31aaa4fa9172c6226765ac044481ffbd88ec
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/util.hpp b/util.hpp
index 3434aca..1d74300 100644
--- a/util.hpp
+++ b/util.hpp
@@ -63,6 +63,12 @@
 
 }
 
+/** @brief Delete the given interface.
+ *  @param[in] intf - interface name.
+ */
+void deleteInterface(const std::string& intf);
+
+
 } //namespace network
 
 class Descriptor