Remove partial blockfile v3 disk_cache implementation.

net/disk_cache/blockfile/rankings.cc

Index: net/disk_cache/blockfile/rankings.cc
diff --git a/net/disk_cache/blockfile/rankings.cc b/net/disk_cache/blockfile/rankings.cc
index 79234f49ee4c3312e026549158a9614df0359648..c5593508ab4b819e791512566581d6b43cb39620 100644
--- a/net/disk_cache/blockfile/rankings.cc
+++ b/net/disk_cache/blockfile/rankings.cc
@@ -542,8 +542,8 @@ bool Rankings::SanityCheck(CacheRankingsBlock* node, bool from_list) const {
 
   Addr next_addr(data->next);
   Addr prev_addr(data->prev);
-  if (!next_addr.SanityCheckV2() || next_addr.file_type() != RANKINGS ||
-      !prev_addr.SanityCheckV2() || prev_addr.file_type() != RANKINGS)
+  if (!next_addr.SanityCheck() || next_addr.file_type() != RANKINGS ||
+      !prev_addr.SanityCheck() || prev_addr.file_type() != RANKINGS)
     return false;
 
   return true;