add an other fairmq logger implementation in case boost version < 1.56 for backward compability

fairmq/logger/fairroot_null_deleter.h

@@ -0,0 +1,27 @@
+/* 
+ * File:   fairroot_null_deleter.h
+ * Author: winckler
+ *
+ * Created on September 21, 2015, 11:50 AM
+ */
+
+#ifndef FAIRROOT_NULL_DELETER_H
+#define	FAIRROOT_NULL_DELETER_H
+// boost like null_deleter introduced for backward compability if boost version < 1.56
+
+namespace fairroot
+{
+    struct null_deleter
+    {
+        //! Function object result type
+        typedef void result_type;
+        /*!
+         * Does nothing
+         */
+        template< typename T >
+        void operator() (T*) const noexcept {}
+    };
+
+}
+#endif	/* FAIRROOT_NULL_DELETER_H */
+