update rocksdb submodule to 6.22.fb

Summary:
6.22.fb is the latest RocksDB release,
aligned to fb-MySQL 5.6.

update-submodule: rocksdb

Reviewed By: yizhang82

Differential Revision: D29476464

fbshipit-source-id: 85ea846d8b0

mysql-test/suite/rocksdb/r/show_engine.result

@@ -205,6 +205,8 @@ __system__	TABLE_FACTORY::READ_AMP_BYTES_PER_BIT	#
 __system__	TABLE_FACTORY::FORMAT_VERSION	#
 __system__	TABLE_FACTORY::ENABLE_INDEX_COMPRESSION	#
 __system__	TABLE_FACTORY::BLOCK_ALIGN	#
+__system__	TABLE_FACTORY::MAX_AUTO_READAHEAD_SIZE	#
+__system__	TABLE_FACTORY::PREPOPULATE_BLOCK_CACHE	#
 cf_t1	COMPARATOR	#
 cf_t1	MERGE_OPERATOR	#
 cf_t1	COMPACTION_FILTER	#
@@ -282,6 +284,8 @@ cf_t1	TABLE_FACTORY::READ_AMP_BYTES_PER_BIT	#
 cf_t1	TABLE_FACTORY::FORMAT_VERSION	#
 cf_t1	TABLE_FACTORY::ENABLE_INDEX_COMPRESSION	#
 cf_t1	TABLE_FACTORY::BLOCK_ALIGN	#
+cf_t1	TABLE_FACTORY::MAX_AUTO_READAHEAD_SIZE	#
+cf_t1	TABLE_FACTORY::PREPOPULATE_BLOCK_CACHE	#
 default	COMPARATOR	#
 default	MERGE_OPERATOR	#
 default	COMPACTION_FILTER	#
@@ -359,6 +363,8 @@ default	TABLE_FACTORY::READ_AMP_BYTES_PER_BIT	#
 default	TABLE_FACTORY::FORMAT_VERSION	#
 default	TABLE_FACTORY::ENABLE_INDEX_COMPRESSION	#
 default	TABLE_FACTORY::BLOCK_ALIGN	#
+default	TABLE_FACTORY::MAX_AUTO_READAHEAD_SIZE	#
+default	TABLE_FACTORY::PREPOPULATE_BLOCK_CACHE	#
 rev:cf_t2	COMPARATOR	#
 rev:cf_t2	MERGE_OPERATOR	#
 rev:cf_t2	COMPACTION_FILTER	#
@@ -436,6 +442,8 @@ rev:cf_t2	TABLE_FACTORY::READ_AMP_BYTES_PER_BIT	#
 rev:cf_t2	TABLE_FACTORY::FORMAT_VERSION	#
 rev:cf_t2	TABLE_FACTORY::ENABLE_INDEX_COMPRESSION	#
 rev:cf_t2	TABLE_FACTORY::BLOCK_ALIGN	#
+rev:cf_t2	TABLE_FACTORY::MAX_AUTO_READAHEAD_SIZE	#
+rev:cf_t2	TABLE_FACTORY::PREPOPULATE_BLOCK_CACHE	#
 DROP TABLE t1;
 DROP TABLE t2;
 DROP TABLE t3;