app client - fix not handling failed return from eldbus call
app client - fix not handling failed return from eldbus call

this fixes CID 1091411

FlorentRevest/Elementary,rvandegrift/elementary,rvandegrift/elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,FlorentRevest/Elementary,rvandegrift/elementary