Fix a bug in svm_read_problem of python/liblinearutil.py so float(val) rather than val is used to detect zero fearue values.
Fix a bug in svm_read_problem of python/liblinearutil.py so float(val) rather than val is used to detect zero fearue values.

cjlin1/liblinear,cjlin1/liblinear,cjlin1/liblinear,cjlin1/liblinear