Wholesale conversion to #pragma once

Kudos to cgmb and https://github.com/cgmb/guardonce

Change-Id: Ifa8970734b8d43fd08c9260c645bdb0228633791
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/plugins/valgrind/callgrind/callgrindrunner.h

@@ -23,8 +23,7 @@
 **
 ****************************************************************************/
 
-#ifndef VALGRIND_CALLGRIND_CALLGRINDRUNNER_H
-#define VALGRIND_CALLGRIND_CALLGRINDRUNNER_H
+#pragma once
 
 #include "../valgrindrunner.h"
 
@@ -68,5 +67,3 @@ private:
 
 } // namespace Callgrind
 } // namespace Valgrind
-
-#endif // VALGRIND_CALLGRIND_CALLGRINDRUNNER_H