Values are now read from kinematics.yaml correctly.

Fixes issue https://github.com/ros-planning/moveit_setup_assistant/issues/99. I wanted to confine the changes to findValue(), but everything I tried caused findValue() to crash.

I would suggest moving this line down into the next #ifdef right above the old iterator statement (yes, it messes with the comment a bit, but it avoids any occurances of #ifndef.