Chasing dead assignments reported by clang-scan

* SAX2.c dict.c error.c hash.c nanohttp.c parser.c python/libxml.c
  relaxng.c runtest.c tree.c valid.c xinclude.c xmlregexp.c xmlsave.c
  xmlschemas.c xpath.c xpointer.c: mostly removing unneded affectations,
  but this led to a few real bugs and some part not yet understood
  (relaxng/interleave)
diff --git a/runtest.c b/runtest.c
index 7640aad..16196ea 100644
--- a/runtest.c
+++ b/runtest.c
@@ -3120,6 +3120,7 @@
 	       filename);
     }
     fclose(schemasOutput);
+    ret = 0;
     if (result) {
 	if (compareFiles(temp, result)) {
 	    fprintf(stderr, "Result for %s on %s failed\n", filename, sch);
@@ -3229,7 +3230,7 @@
     globfree(&globbuf);
     xmlRelaxNGFree(schemas);
 
-    return(res);
+    return(ret);
 }
 
 #ifdef LIBXML_READER_ENABLED