devtool: add: delete externalsrc files on npm recipe do_install
The npm class just installs whatever is in ${S}; if you're using
externalsrc in conjunction with it the symlinks (oe-workdir and oe-logs
by default) plus singletask.lock will end up in the final package, which
isn't really right. Introduce a variable so we know the path the files
will be installed into within npm.bbclass, and append to do_install
within the workspace bbappend to delete the files.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
