Explicity select what is copied inside the DKMS source tree

Explicity select what is copied inside the DKMS source tree

 * We use the variable DKMSFILES to explicity select wich files
   or directories are copied inside the DKMS source tree.

 * Once copied. We rewrite configure.ac with awk to remove the
   userland/misc components and only keep the kernel stuff that
   is needed by DKMS.

   * The awk lines deletes from inside AC_CONFIG_FILES([]) of configure.ac
     everything except:
	(Makefile$|include/|module/|*.release$|dkms.conf$)

   * Then we run ./autogen.sh to generate the configure scripts
     inside the DKMS source tree

 * This allows us to ship a clean DKMS source tree with *only* the kernel
   components and free from the userland/misc ones (ex: splat)

    * Prevents manual build on the DKMS source tree.