"make install" should not rebuild librealsense.so
"make install" should not rebuild librealsense.so

The 'library' phony target that 'install' depended on forced the library
to be rebuilt.  Since 'make install' is usually invoked by root, whose
build environment may differ, the rebuild can fail.  This removes the
unconventional phony targets so that nothing gets remade unnecessarily.

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