rocksdb: sync with upstream

to pickup the fix of https://github.com/facebook/rocksdb/pull/2692.

Signed-off-by: Kefu Chai <kchai@redhat.com>

diff --git a/src/rocksdb b/src/rocksdb
index e15382c09c87a65eaeca9bda233bab503f1e5772..382277d0fe79ece86b799e3925919cf44c3afb4c 160000 (submodule)
--- a/src/rocksdb
+++ b/src/rocksdb
@@ -1 +1 @@
-Subproject commit e15382c09c87a65eaeca9bda233bab503f1e5772
+Subproject commit 382277d0fe79ece86b799e3925919cf44c3afb4c