LU-18807 utils: SIGSEGV in jt_obd_setattr

LU-18807 utils: SIGSEGV in jt_obd_setattr

Wrong argument comparison causes crash. Also unchecked
yaml_scalar_event_initialize() causes a double free problem.
This should be done for all variable based event initialization.

Test-Parameters: trivial
Signed-off-by: Frank Sehr <fsehr@whamcloud.com>
Change-Id: Id90aec86d0779316dd7ca3d1d926a3db5503d2c1
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58403
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Manish Regmi <mregmi@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>