partial_clone_get_default_filter_spec has no callers

[Ramsay Jones]

Hi Jeff,

commit f1862e8153 ("partial-clone: define partial clone settings
in config", 2017-12-05), which is part of your 'jh/partial-clone'
branch, introduces the partial_clone_get_default_filter_spec()
function without any callers. Could you please confirm that this
is intentional and that, presumably, a future series will include
a call to this function.

Thanks!

ATB,
Ramsay Jones