Fix exception type in forwardKinematics python binding.
Fix exception type in forwardKinematics python binding.

gergondet/RBDyn,gergondet/RBDyn,gergondet/RBDyn,jrl-umi3218/RBDyn,jrl-umi3218/RBDyn,jrl-umi3218/RBDyn,gergondet/RBDyn,gergondet/RBDyn,jrl-umi3218/RBDyn