package/nodejs: bump version to 6.9.1
https://nodejs.org/en/blog/release/v6.9.1/
The patches from 6.7.0 have been copied to 6.9.1.
Signed-off-by: Patrick Devlin <cloudyparts@icloud.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>