leveldb: Update submodule

Signed-off-by: Gary Lowell <gary.lowell@inktank.com>

diff --git a/src/leveldb b/src/leveldb
index f2d406b4213a22bfed3acfdb071fbec9ca9205cc..c79c270174307411819ddfdd8c9b671ec4fb69c9 160000 (submodule)
--- a/src/leveldb
+++ b/src/leveldb
@@ -1 +1 @@
-Subproject commit f2d406b4213a22bfed3acfdb071fbec9ca9205cc
+Subproject commit c79c270174307411819ddfdd8c9b671ec4fb69c9