src/interface: use #pragma once in headers

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>

src/interface/interface_driver.h

@@ -18,12 +18,9 @@
  * <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBVIRT_INTERFACE_DRIVER_H
-# define LIBVIRT_INTERFACE_DRIVER_H
+#pragma once
 
 int interfaceRegister(void);
 
 int netcfIfaceRegister(void);
 int udevIfaceRegister(void);
-
-#endif /* LIBVIRT_INTERFACE_DRIVER_H */