YKD: Fix loading of YKD quorum module

Although YKD is currently unsupported, untested and decprecated it's
handy for testing things in the quorum module.

This patch allows YKD to actually load without an error. It does not fix
anything else in the service!

Also remove vsftype and its reference to YKD being the preferred and
default provider from the corosync.conf man page,
as that hasn't been true for a considerable time.

Signed-off-by: Christine Caulfield <ccaulfie@redhat.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>

exec/vsf_ykd.c

@@ -512,7 +512,7 @@ char *ykd_init (
 	struct corosync_api_v1 *corosync_api,
 	quorum_set_quorate_fn_t set_primary)
 {
-	const char *error = "";
+	const char *error = NULL;
 
 	ykd_primary_callback_fn = set_primary;
 	api = corosync_api;

man/corosync.conf.5

@@ -237,18 +237,6 @@ Choose hardware carefully if intending to use large frame support.
 
 The default is 1500.
 
-.TP
-vsftype
-This directive controls the virtual synchrony filter type used to identify
-a primary component.  The preferred choice is YKD dynamic linear voting,
-however, for clusters larger then 32 nodes YKD consumes alot of memory.  For
-large scale clusters that are created by changing the MAX_PROCESSORS_COUNT
-#define in the C code totem.h file, the virtual synchrony filter "none" is
-recommended but then AMF and DLCK services (which are currently experimental)
-are not safe for use.
-
-The default is ykd.  The vsftype can also be set to none.
-
 .TP
 transport
 This directive controls the transport mechanism used.  If the interface to