largefiles: fix misleading comments in lfutil instore and storepath
Problem in both cases is cache in largefiles has assigned
meaning - user cache which is additional place to get/put
files. Those two function works on store - the main place
to store largefiles in the repository - .hg/largefiles and
using "cache" to describe it is misleading.
https://bz.mercurial-scm.org/1089
$ hg init
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b (glob)
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b (glob)
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..