From Ioan: fix crashing bug.
From Ioan: fix crashing bug.

--HG--
extra : convert_revision : 39fabbb91c92c7cfcaf2c0adc3c53e2e9c251af0

davetcoleman/ompl,utiasASRL/batch-informed-trees,sonny-tarbouriech/ompl,davetcoleman/ompl,davetcoleman/ompl,sonny-tarbouriech/ompl,florianhauer/ompl,jvgomez/ompl,florianhauer/ompl,sonny-tarbouriech/ompl,sonny-tarbouriech/ompl,jvgomez/ompl,utiasASRL/batch-informed-trees,florianhauer/ompl,jvgomez/ompl,utiasASRL/batch-informed-trees,florianhauer/ompl,utiasASRL/batch-informed-trees,utiasASRL/batch-informed-trees,davetcoleman/ompl,florianhauer/ompl,utiasASRL/batch-informed-trees,jvgomez/ompl,sonny-tarbouriech/ompl,sonny-tarbouriech/ompl,davetcoleman/ompl,jvgomez/ompl,florianhauer/ompl,davetcoleman/ompl,jvgomez/ompl