LU-6766 utils: remove llapi_quotachown() and cb_quotachown()

LU-6766 utils: remove llapi_quotachown() and cb_quotachown()

The SYS_chown syscall is not available on arm64, but the functions
llapi_quotachown() and cb_quotachown() are not needed anymore and
should have been removed in the patch
http://review.whamcloud.com/4022

Change-Id: I11fa4ab901327c1c8bcfb7e6dfe14a955e2f2618
Signed-off-by: Arnaud Guignard <arnaud.guignard@cea.fr>
Reviewed-on: http://review.whamcloud.com/15396
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>