Implemented RegFlushKey and NtFlushKey.

diff --git a/server/request.h b/server/request.h
index ec2d5a1..fcd95ab 100644
--- a/server/request.h
+++ b/server/request.h
@@ -200,6 +200,7 @@
 DECL_HANDLER(create_key);
 DECL_HANDLER(open_key);
 DECL_HANDLER(delete_key);
+DECL_HANDLER(flush_key);
 DECL_HANDLER(enum_key);
 DECL_HANDLER(set_key_value);
 DECL_HANDLER(get_key_value);
@@ -388,6 +389,7 @@
     (req_handler)req_create_key,
     (req_handler)req_open_key,
     (req_handler)req_delete_key,
+    (req_handler)req_flush_key,
     (req_handler)req_enum_key,
     (req_handler)req_set_key_value,
     (req_handler)req_get_key_value,