leveldb: fix-up submodule entry.

diff --git a/src/leveldb b/src/leveldb
index be23f7880b64514de1c727b86f0ccefe5540519e..f2d406b4213a22bfed3acfdb071fbec9ca9205cc 160000 (submodule)
--- a/src/leveldb
+++ b/src/leveldb
@@ -1 +1 @@
-Subproject commit be23f7880b64514de1c727b86f0ccefe5540519e
+Subproject commit f2d406b4213a22bfed3acfdb071fbec9ca9205cc