scmutil: rename filecacheentry to filecachesubentry

Upcoming patches will allow the file cache to watch over multiple files, and
call the decorated function again if any of the files change.

The particular use case for this is the bookmark store, which needs to be
invalidated if either .hg/bookmarks or .hg/bookmarks.current changes. (This
doesn't currently happen, which is a bug. This bug will also be fixed in
upcoming patches.)

mercurial/scmutil.py

@@ -713,14 +713,14 b' def readrequires(opener, supported):'
               "Mercurial)") % "', '".join(missings))
     return requirements
 
-class filecacheentry(object):
+class filecachesubentry(object):
     def __init__(self, path, stat):
         self.path = path
         self.cachestat = None
         self._cacheable = None
 
         if stat:
-            self.cachestat = filecacheentry.stat(self.path)
+            self.cachestat = filecachesubentry.stat(self.path)
 
             if self.cachestat:
                 self._cacheable = self.cachestat.cacheable()
@@ -730,7 +730,7 b' class filecacheentry(object):'
 
     def refresh(self):
         if self.cacheable():
-            self.cachestat = filecacheentry.stat(self.path)
+            self.cachestat = filecachesubentry.stat(self.path)
 
     def cacheable(self):
         if self._cacheable is not None:
@@ -744,7 +744,7 b' class filecacheentry(object):'
         if not self.cacheable():
             return True
 
-        newstat = filecacheentry.stat(self.path)
+        newstat = filecachesubentry.stat(self.path)
 
         # we may not know if it's cacheable yet, check again now
         if newstat and self._cacheable is None:
@@ -814,7 +814,7 b' class filecache(object):'
 
             # We stat -before- creating the object so our cache doesn't lie if
             # a writer modified between the time we read and stat
-            entry = filecacheentry(path, True)
+            entry = filecachesubentry(path, True)
             entry.obj = self.func(obj)
 
             obj._filecache[self.name] = entry
@@ -826,7 +826,7 b' class filecache(object):'
         if self.name not in obj._filecache:
             # we add an entry for the missing value because X in __dict__
             # implies X in _filecache
-            ce = filecacheentry(self.join(obj, self.path), False)
+            ce = filecachesubentry(self.join(obj, self.path), False)
             obj._filecache[self.name] = ce
         else:
             ce = obj._filecache[self.name]