make sure that install space exists when creating env.sh file for cmake projects (fix #340)
make sure that install space exists when creating env.sh file for cmake projects (fix #340)

meyerj/catkin,asmodehn/catkin,beni55/catkin,shyamalschandra/catkin,jack-oquin/catkin,wkentaro/catkin,scpeters/catkin,thaddeustaylor/catkin,wkentaro/catkin,beni55/catkin,wkentaro/catkin,jack-oquin/catkin,harmishhk/catkin,harmishhk/catkin,thaddeustaylor/catkin,scpeters/catkin,meyerj/catkin,jack-oquin/catkin,ros/catkin,asmodehn/catkin,ros/catkin,shyamalschandra/catkin,shyamalschandra/catkin,scpeters/catkin,beni55/catkin,harmishhk/catkin,meyerj/catkin,thaddeustaylor/catkin,asmodehn/catkin,ros/catkin