make CMakeList.txt less screaming
make CMakeList.txt less screaming

and adhere to the style of the rest of CMakeList.txt

Signed-off-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
(cherry picked from commit 7f958996668f463ee316d4e8d74a71a7bce03a9a)

# Conflicts:
#	CMakeLists.txt

IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense