LU-10327 test: use nogroup instead of nobody

LU-10327 test: use nogroup instead of nobody

In Ubuntu, there isn't any nobody group

Change-Id: I2d4607b3d1384d2d619dd9640363533f92397356
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/30559
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>