LU-10663 utils: clear errno before check

LU-10663 utils: clear errno before check

In jt_obd_destroy() clear errno before calling strtoull() and checking
it.

Test-Parameters: testlist=obdfilter-survey

Lustre-change: https://review.whamcloud.com/#/c/31305/
Lustre-commit: 9e488fe9413184e61dcf405c9c87ca348dd6824a

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I686cd6eb0a57248177e5b0878df5e3f450fbc942
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/31430
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>