[PATCH 4 of 6] cat: migrate to the fileprefetch callback mechanism

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1518328282 18000
#      Sun Feb 11 00:51:22 2018 -0500
# Node ID 10a1e5ef22e820e5b64da9010cb54b597e68d400
# Parent  e4d461d1b9d71253a4563cc6ed7401b6bad32764
cat: migrate to the fileprefetch callback mechanism

diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -2188,14 +2188,14 @@
         mfnode = ctx.manifestnode()
         try:
             if mfnode and mfl[mfnode].find(file)[0]:
-                _prefetchfiles(repo, ctx, [file])
+                fileprefetchhooks(repo, ctx, [file])
                 write(file)
                 return 0
         except KeyError:
             pass
 
     files = [f for f in ctx.walk(matcher)]
-    _prefetchfiles(repo, ctx, files)
+    fileprefetchhooks(repo, ctx, files)
 
     for abs in files:
         write(abs)