staging/lustre: Update header license for lustre_dlm_flags.h

lustre_dlm_flags.h was autogenerated with a wrong script that
mistakenly stated it is GPLv3 when in fact it should be GPLv2.

Also since we are no longer autogenerating this header, drop
all such mentionings.

Reported by: George G. Davis <ggdavisiv@gmail.com>

Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6599
Reviewed-on: http://review.whamcloud.com/14797


Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
CC: George G. Davis <ggdavisiv@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>