reduce k_fold parameter

modules/ml/src/svm.cpp

@@ -1442,7 +1442,7 @@ public:
             //check that while cross-validation there were the samples from all the classes
             if( class_ranges[class_count] <= 0 )
                 CV_Error( CV_StsBadArg, "While cross-validation one or more of the classes have "
-                "been fell out of the sample. Try to enlarge <Params::k_fold>" );
+                "been fell out of the sample. Try to reduce <Params::k_fold>" );
 
             if( svmType == NU_SVC )
             {