lfs: add the ability to disable the usercache
While the usercache is important for real world uses, I've been tripped up more
than a couple of times by it in tests- thinking a file was being downloaded, but
it was simply linked from the local cache. The syntax for setting it is the
same as for setting a null remote endpoint, and like that endpoint, is left
undocumented.
This may or may not be a useful feature in the real world (I'd expect any sane
filesystem to support hardlinks at this point).
pager.pager=p0 # $TESTTMP/sysrc:4
ui.editor=e1 # $TESTTMP/userrc:2
pager.pager=p2 # $PAGER
ui.editor=e1 # $TESTTMP/userrc:2