svm-easy can't find helper programs

[Scott Pakin]

svm-easy can't find its external helper programs:

$ svm-easy heart_scale.txt
Traceback (most recent call last):
  File "/usr/bin/svm-easy", line 28, in <module>
    assert os.path.exists(svmscale_exe),"svm-scale executable not found"
AssertionError: svm-scale executable not found

This is because svm-easy points to a relative directory (..) instead of an absolute directory (/usr/bin) for svm-scale, svm-train, and svm-predict:

 svmscale_exe = "../svm-scale"
 svmtrain_exe = "../svm-train"
 svmpredict_exe = "../svm-predict"
 grid_py = "./grid.py"
 gnuplot_exe = "/usr/bin/gnuplot"

Furthermore, grid.py does not appear to be included in the package. (It can be found at https://raw.githubusercontent.com/cjlin1/libsvm/master/tools/grid.py)

This bug report is for Ubuntu 20.10 (Groovy) and libsvm-tools 3.24+ds-4 on x86_64.