staging:lustre:lnet: lib-md.c erase C99 // comments

After changing the comments format, the other error disappears.
So silences two checkpatch errors:
  ERROR: do not use C99 // comments
  ERROR: trailing statements should be on next line

Signed-off-by: Janet Liu <jianhua.ljh@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>