Replace the last 'dircache's by 'index'

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-ls-files.txt

@@ -124,7 +124,7 @@ which case it outputs:
 detailed information on unmerged paths.
 
 For an unmerged path, instead of recording a single mode/SHA1 pair,
-the dircache records up to three such pairs; one from tree O in stage
+the index records up to three such pairs; one from tree O in stage
 1, A in stage 2, and B in stage 3.  This information can be used by
 the user (or the porcelain) to see what should eventually be recorded at the
 path. (see git-read-tree for more information on state)

diff.c

@@ -1258,7 +1258,7 @@ void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 }
 
 /*
- * Given a name and sha1 pair, if the dircache tells us the file in
+ * Given a name and sha1 pair, if the index tells us the file in
  * the work tree has that object contents, return true, so that
  * prepare_temp_file() does not have to inflate and extract.
  */