Roll leveldb to r71.

The only change applicable to chromium is a fix for a bug 
that causes corruption. The corruption manifests as a missing 
sst file that renders the database unopenable.

BUG=168649


Review URL: https://chromiumcodereview.appspot.com/11775018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175442 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -94,7 +94,7 @@ deps = {
     "/trunk/src@247",
 
   "src/third_party/leveldatabase/src":
-    (Var("googlecode_url") % "leveldb") + "/trunk@68",
+    (Var("googlecode_url") % "leveldb") + "/trunk@71",
 
   "src/third_party/snappy/src":
     (Var("googlecode_url") % "snappy") + "/trunk@63",

third_party/leveldatabase/README.chromium

 Name: LevelDB: A Fast Persistent Key-Value Store
 Short Name: leveldb
 URL: http://code.google.com/p/leveldb/
-Version: r68
+Version: r71
 License: New BSD
 License File: src/LICENSE
 Security Critical: yes