Prevent memory leaks when Adaptation::AccessCheck callback ends the job.

Prevent memory leaks when Adaptation::AccessCheck callback ends the job.

The AccessCheckCallbackWrapper is used in nonBlockingCheck() and is called
from the ACL code, using legacy function-based API.  If the job ends during
the callback processing, there are no AsyncCall wrappers to destroy the job
object. We now convert legacy to async call to enable proper wrapping and job
destruction.

These kind of job leaks are invisible to valgrind, but that is another bug.