patch from Daniel Zimmermann fixing a memory leak in an edge case, solves

* threads.c: patch from Daniel Zimmermann fixing a memory leak
  in an edge case, solves #562230
Daniel

svn path=/trunk/; revision=3809
diff --git a/threads.c b/threads.c
index 23cb200..fde0a62 100644
--- a/threads.c
+++ b/threads.c
@@ -698,6 +698,7 @@
 	if (p == NULL) {
             xmlGenericError(xmlGenericErrorContext,
                             "xmlGetGlobalState: out of memory\n");
+            xmlFreeGlobalState(tsd);
 	    return(NULL);
 	}
         p->memory = tsd;