fixed CvRTrees::read in case nactive_vars==var_count (thanks to Malcolm Reynolds)

modules/ml/src/rtrees.cpp

@@ -813,13 +813,18 @@ void CvRTrees::read( CvFileStorage* fs, CvFileNode* fnode )
     active_var_mask = cvCreateMat( 1, var_count, CV_8UC1 );
     {
         // initialize active variables mask
-        CvMat submask1, submask2;
+        CvMat submask1;
 		cvGetCols( active_var_mask, &submask1, 0, nactive_vars );
-        cvGetCols( active_var_mask, &submask2, nactive_vars, var_count );
         cvSet( &submask1, cvScalar(1) );
+
+		if( nactive_vars < var_count )
+		{
+			CvMat submask2;
+			cvGetCols( active_var_mask, &submask2, nactive_vars, var_count );
 			cvZero( &submask2 );
 		}
     }
+}
 
 
 int CvRTrees::get_tree_count() const