qapi/migration.json: Rename COLO unknown mode to none mode.

Suggested by Markus Armbruster rename COLO unknown mode to none mode.
Signed-off-by: NZhang Chen <zhangckid@gmail.com>
Signed-off-by: NZhang Chen <chen.zhang@intel.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

migration/colo-failover.c

@@ -77,7 +77,7 @@ FailoverStatus failover_get_state(void)
 
 void qmp_x_colo_lost_heartbeat(Error **errp)
 {
-    if (get_colo_mode() == COLO_MODE_UNKNOWN) {
+    if (get_colo_mode() == COLO_MODE_NONE) {
         error_setg(errp, QERR_FEATURE_DISABLED, "colo");
         return;
     }

migration/colo.c

@@ -160,7 +160,7 @@ COLOMode get_colo_mode(void)
     } else if (migration_incoming_in_colo_state()) {
         return COLO_MODE_SECONDARY;
     } else {
-        return COLO_MODE_UNKNOWN;
+        return COLO_MODE_NONE;
     }
 }
 

qapi/migration.json

@@ -923,18 +923,18 @@
 ##
 # @COLOMode:
 #
-# The colo mode
+# The COLO current mode.
 #
-# @unknown: unknown mode
+# @none: COLO is disabled.
 #
-# @primary: master side
+# @primary: COLO node in primary side.
 #
-# @secondary: slave side
+# @secondary: COLO node in slave side.
 #
 # Since: 2.8
 ##
 { 'enum': 'COLOMode',
-  'data': [ 'unknown', 'primary', 'secondary'] }
+  'data': [ 'none', 'primary', 'secondary'] }
 
 ##
 # @FailoverStatus: