Fix use-after-free with xmllint --html --push

Call htmlCtxtUseOptions to make sure that names aren't stored in
dictionaries.

Note that this issue only affects xmllint using the HTML push parser.

Fixes #230.

xmllint.c

@@ -2213,7 +2213,7 @@ static void parseAndPrintFile(char *filename, xmlParserCtxtPtr rectxt) {
             if (res > 0) {
                 ctxt = htmlCreatePushParserCtxt(NULL, NULL,
                             chars, res, filename, XML_CHAR_ENCODING_NONE);
-                xmlCtxtUseOptions(ctxt, options);
+                htmlCtxtUseOptions(ctxt, options);
                 while ((res = fread(chars, 1, pushsize, f)) > 0) {
                     htmlParseChunk(ctxt, chars, res, 0);
                 }