storage: Give up lease acquisition when draining
storage: Give up lease acquisition when draining

This establishes parity with the other case (in which the task does not even
get started) and should address a relatively common reason for an invocation
of `./cockroach quit` to run into the hard limit.

paperstreet/cockroach,cockroachdb/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,sunya123/cockroach,maxlang/cockroach,sunya123/cockroach,cockroachdb/cockroach,paperstreet/cockroach,glycerine/cockroach,petermattis/cockroach,veteranlu/cockroach,cockroachdb/cockroach,vivekmenezes/cockroach,glycerine/cockroach,paperstreet/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,sunya123/cockroach,veteranlu/cockroach,glycerine/cockroach,paperstreet/cockroach,glycerine/cockroach,maxlang/cockroach,petermattis/cockroach,petermattis/cockroach,veteranlu/cockroach,cockroachdb/cockroach,vaibhavarora/cockroach,cockroachdb/cockroach,arjun4084346/cockroach,sunya123/cockroach,veteranlu/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,glycerine/cockroach,veteranlu/cockroach,veteranlu/cockroach,petermattis/cockroach,sunya123/cockroach,cockroachdb/cockroach,sunya123/cockroach,arjun4084346/cockroach,arjun4084346/cockroach,vivekmenezes/cockroach,maxlang/cockroach,paperstreet/cockroach,maxlang/cockroach,arjun4084346/cockroach,cockroachdb/cockroach,vivekmenezes/cockroach,vivekmenezes/cockroach,veteranlu/cockroach,glycerine/cockroach,maxlang/cockroach,vaibhavarora/cockroach,petermattis/cockroach,maxlang/cockroach,arjun4084346/cockroach,vivekmenezes/cockroach,veteranlu/cockroach,paperstreet/cockroach,petermattis/cockroach,vivekmenezes/cockroach,arjun4084346/cockroach,glycerine/cockroach,sunya123/cockroach,sunya123/cockroach,vivekmenezes/cockroach,maxlang/cockroach,arjun4084346/cockroach,vivekmenezes/cockroach,arjun4084346/cockroach,glycerine/cockroach,maxlang/cockroach,petermattis/cockroach,cockroachdb/cockroach,petermattis/cockroach,vaibhavarora/cockroach