Removed the '-1' key in the support vector representation.
Removed the '-1' key in the support vector representation.

The function get_SV() in svm.py returns the support vectors.
It accidently adds a '-1' key in the dictionary that represents
a support vector.

The '-1' is used by the C implementation to denote the last
svm_node in the training set x.

Signed-off-by: Chih-Jen Lin <79ef78d58a17c54482a31255666a689b188960a6@csie.ntu.edu.tw>

cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm