commit 00bd8edb upstream.

send_mds_reconnect() may call discard_cap_releases() after all
release messages have been dropped by cleanup_cap_releases()
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Cc: Markus Blank-Burian <burian@muenster.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>