re-add include protection for TF1- they were removed by mistake

git-svn-id: http://root.cern.ch/svn/root/trunk@22615 27541ba8-7e3a-0410-8455-c3a389f83636

hist/inc/Math/WrappedMultiTF1.h

@@ -18,8 +18,9 @@
 #include "Math/IParamFunction.h"
 #endif
 
-
+#ifndef ROOT_TF1
 #include "TF1.h"
+#endif
 
 namespace ROOT { 
 

hist/inc/Math/WrappedTF1.h

@@ -18,8 +18,9 @@
 #include "Math/IParamFunction.h"
 #endif
 
-
+#ifndef ROOT_TF1
 #include "TF1.h"
+#endif
 #include <cmath>
 
 namespace ROOT {