Fix for CvSVM tutorial documentation (Bugfix #3973)

In the OpenCV machine learning tutorial: [[http://docs.opencv.org/doc/tutorials/ml/introduction_to_svm/introduction_to_svm.html#explanation]] **Explanation** *1.Set up the training data* The training data of this exercise is formed by a set of labeled 2D-points that belong to one of two different classes; one of the classes consists of one point and the other of three points. float labels[4] = {1.0, -1.0, -1.0, -1.0}; float trainingData[4][2] = {{501, 10}, {255, 10}, {501, 255}, {10, 501}}; The function CvSVM::train that will be used afterwards requires the training data to be stored as Mat objects of floats. Therefore, we create these objects from the arrays defined above: -Mat trainingDataMat(3, 2, CV_32FC1, trainingData);- -Mat labelsMat (3, 1, CV_32FC1, labels);- The Mat dimension initiating is wrong. It should be fixed as: +Mat trainingDataMat(4, 2, CV_32FC1, trainingData);+ +Mat labelsMat (4, 1, CV_32FC1, labels);+