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.
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ ls
a
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
B should disappear
$ ls
a