LU-349 set LC_ALL explicitly in obdfilter-survey

LU-349 set LC_ALL explicitly in obdfilter-survey

in lustre-iokit/obdfilter-survey/obdfilter-survery, different locales will
cause the "awk" to fail, setting LC_ALL=POSIX explicitly to avoid the issue.

Change-Id: I9a84f9c93a9911f3a84c33429ba5cc9981913995
Signed-off-by: Hongchao Zhang <hongchao.zhang@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/594
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>