log: use an exact matcher for --patch --follow

The arguments to log --patch --follow are expected to be exact paths.

This will be used to make manifest filtering for these cases more efficient in
upcoming patches.

mercurial/cmdutil.py

@@ -1499,7 +1499,6 b' def _makelogfilematcher(repo, files, fol'
     fcache = {}
     fcacheready = [False]
     pctx = repo['.']
-    wctx = repo[None]
 
     def populate():
         for fn in files:
@@ -1512,7 +1511,7 b' def _makelogfilematcher(repo, files, fol'
             # Lazy initialization
             fcacheready[0] = True
             populate()
-        return scmutil.match(wctx, fcache.get(rev, []), default='path')
+        return scmutil.matchfiles(repo, fcache.get(rev, []))
 
     return filematcher