This does now mean that modules won't go to /usr/local with the default prefix
but may instead try to install in /usr/lib. However if using nvm they should go
to the right place as long as NODE_ROOT_DIR is set correctly. This commit
changes NODE_ROOT_DIR to actually refer to the root directory of node rather
than the include dir which is what FindNodejs gets
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
