wsman-soap-envelope: Check right variable for NULL

Wrong variable was checked for NULL: node instead of object.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
diff --git a/src/lib/wsman-soap-envelope.c b/src/lib/wsman-soap-envelope.c
index 8b908c7..fd88cd5 100644
--- a/src/lib/wsman-soap-envelope.c
+++ b/src/lib/wsman-soap-envelope.c
@@ -1262,7 +1262,7 @@
 	}
 
 	object = ws_xml_get_child(assInst, 0, XML_NS_CIM_BINDING, WSMB_OBJECT);
-	if(!node) {
+	if(!object) {
 		debug("no SelectorSet defined. Missing Object");
 		return NULL;
 	}