Fix #356: fix value of SPS::m_numRPL0/1

Set SPS::m_numRPL0/1 equal to num_ref_pic_lists_in_sps instead of num_ref_pic_lists_in_sps + 1.
This allow to align the parsing of slice_header with specification when
getNumRPL0() or getNumRPL1() are called (correspond to the condition on
num_ref_pic_lists_in_sps in the specfication).
Status Job ID Name Coverage
  External
passed jenkins