migration: fix applying wrong capabilities

When setting migration capabilities via QMP/HMP, we'll apply them even
if the capability check failed.  Fix it.

Fixes: 4a84214ebe ("migration: provide migrate_caps_check()", 2017-07-18)
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180305094938.31374-1-peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

migration/migration.c

@@ -747,13 +747,15 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
 {
     MigrationState *s = migrate_get_current();
     MigrationCapabilityStatusList *cap;
+    bool cap_list[MIGRATION_CAPABILITY__MAX];
 
     if (migration_is_setup_or_active(s->state)) {
         error_setg(errp, QERR_MIGRATION_ACTIVE);
         return;
     }
 
-    if (!migrate_caps_check(s->enabled_capabilities, params, errp)) {
+    memcpy(cap_list, s->enabled_capabilities, sizeof(cap_list));
+    if (!migrate_caps_check(cap_list, params, errp)) {
         return;
     }