Linux build: properly install built kernel module

Linux build: properly install built kernel module

Fix a problem introduced by the recent parallel make patches - the
resulting kernel module was not getting copied to the install or
dest location.
Copy some of the code from the COMPDIRS target for INSTDIRS and
DESTDIRS.  We still have to call into the lower level make and have it
install the module.

Reviewed-on: http://gerrit.openafs.org/67
Verified-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>