small change to remove compiler warning
small change to remove compiler warning

--HG--
branch : syclop

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