rocksdb: debug log writes/reads

Signed-off-by: Sage Weil <sage@redhat.com>

diff --git a/src/rocksdb b/src/rocksdb
index 8a23156804ef86749ba767d672d8a05462d9891b..fa98456ccbd860120127ac2e91a2088fb222606e 160000 (submodule)
--- a/src/rocksdb
+++ b/src/rocksdb
@@ -1 +1 @@
-Subproject commit 8a23156804ef86749ba767d672d8a05462d9891b
+Subproject commit fa98456ccbd860120127ac2e91a2088fb222606e