v1.6.32 - Keep no longer asks for the whole cache budget twice

Keep held back the full cache budget plus 10% beside the title, even when the cache already filled
most of that budget on disk. On a small disk it refused titles that fitted — a 3 GB film on a disk
with 26 GB free, under a 30 GB budget. It now holds back only the room the cache can still grow
into, plus the 10%. An empty cache gets the same reserve as before, and a title that would fill the
disk is still refused. Thanks to jaison for the report.

Upgrade: pull it.