libceph: Get secret from the kernel keys api when mounting with key=NAME.

Signed-off-by: Tommi Virtanen <tommi.virtanen@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>

net/ceph/Kconfig

diff --git a/net/ceph/Kconfig b/net/ceph/Kconfig
index ad42404..be683f2 100644
--- a/net/ceph/Kconfig
+++ b/net/ceph/Kconfig
@@ -4,6 +4,7 @@
 	select LIBCRC32C
 	select CRYPTO_AES
 	select CRYPTO
+	select KEYS
 	default n
 	help
 	  Choose Y or M here to include cephlib, which provides the