lfs: fix a discrepancy with a function wanting a filelog, but calling it rlog

This conceptually broke in 1541e1a8e87d when the filelog isa revlog relationship
was changed to containment of the revlog.  It was made more obvious in
62a532045e71 and related API simplification.

It's resolved in favor of passing a revlog because the revlog verification code
doesn't have a reference to a filelog.

Differential Revision: https://phab.mercurial-scm.org/D7711

hgext/lfs/wrapper.py

@@ -151,12 +151,12 b' def _islfs(rlog, node=None, rev=None):'
         if node is None:
             # both None - likely working copy content where node is not ready
             return False
-        rev = rlog._revlog.rev(node)
+        rev = rlog.rev(node)
     else:
-        node = rlog._revlog.node(rev)
+        node = rlog.node(rev)
     if node == nullid:
         return False
-    flags = rlog._revlog.flags(rev)
+    flags = rlog.flags(rev)
     return bool(flags & revlog.REVIDX_EXTSTORED)
 
 
@@ -203,7 +203,7 b' def filelogaddrevision('
 
 # Wrapping may also be applied by remotefilelog
 def filelogrenamed(orig, self, node):
-    if _islfs(self, node):
+    if _islfs(self._revlog, node):
         rawtext = self._revlog.rawdata(node)
         if not rawtext:
             return False
@@ -217,7 +217,7 b' def filelogrenamed(orig, self, node):'
 
 # Wrapping may also be applied by remotefilelog
 def filelogsize(orig, self, rev):
-    if _islfs(self, rev=rev):
+    if _islfs(self._revlog, rev=rev):
         # fast path: use lfs metadata to answer size
         rawtext = self._revlog.rawdata(rev)
         metadata = pointer.deserialize(rawtext)
@@ -248,7 +248,7 b' def filectxisbinary(orig, self):'
 
 
 def filectxislfs(self):
-    return _islfs(self.filelog(), self.filenode())
+    return _islfs(self.filelog()._revlog, self.filenode())
 
 
 @eh.wrapfunction(cmdutil, b'_updatecatformatter')
@@ -459,7 +459,7 b' def pointerfromctx(ctx, f, removed=False'
         else:
             return None
     fctx = _ctx[f]
-    if not _islfs(fctx.filelog(), fctx.filenode()):
+    if not _islfs(fctx.filelog()._revlog, fctx.filenode()):
         return None
     try:
         p = pointer.deserialize(fctx.rawdata())