make sure target isn't SENTINEL before calling targetService
make sure target isn't SENTINEL before calling targetService

Change-Id: I474e127dcd2f543cf8e04488de7de5932f4b4c96
CQ: SW291807
Backport: release-fips820
Reviewed-on: http://gfw160.aus.stglabs.ibm.com:8080/gerrit/15150
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>

Over-enthusiastic/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot,csmart/hostboot,alvintpwang/hostboot,csmart/hostboot,csmart/hostboot,alvintpwang/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,alvintpwang/hostboot,csmart/hostboot,open-power/hostboot