nfsd: v4 support requires CRYPTO

nfsd V4 support uses crypto interfaces, so select CRYPTO
to fix build errors in 2.6.39:

ERROR: "crypto_destroy_tfm" [fs/nfsd/nfsd.ko] undefined!
ERROR: "crypto_alloc_base" [fs/nfsd/nfsd.ko] undefined!
Reported-by: Wakko Warner <wakko@animx.eu.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/Kconfig

@@ -82,6 +82,7 @@ config NFSD_V4
 	select NFSD_V3
 	select FS_POSIX_ACL
 	select SUNRPC_GSS
+	select CRYPTO
 	help
 	  This option enables support in your system's NFS server for
 	  version 4 of the NFS protocol (RFC 3530).