Fix crash when getting preview with long html tags

Closes: bgo #726468

THANKS

@@ -20,6 +20,7 @@ Mathias Hasselmann <mathias@openismus.com>
 Timo Kluck <tkluck@infty.nl>
 Charles Lehner <rdm.cel@celehner.com>
 Avi Levy <avi.w.levy@gmail.com>
+Simon Lipp <bugs-gnome@simon.lipp.name>
 Brendan Long <self@brendanlong.com>
 Angelo Marchesin <marchesin.angelo@gmail.com>
 Kai Mast <mail@kai-mast.de>

src/engine/util/util-html.vala

@@ -124,9 +124,8 @@ public string remove_html_tags(string input) {
         Regex style = new Regex("<style[^>]*?>[\\s\\S]*?<\\/style>", RegexCompileFlags.CASELESS);
         output = style.replace(output, -1, 0, "");
         
-        // Removes remaining tags. Based on this regex:
-        // http://osherove.com/blog/2003/5/13/strip-html-tags-from-a-string-using-regular-expressions.html
-        Regex tags = new Regex("<(.|\n)*?>", RegexCompileFlags.CASELESS);
+        // Removes remaining tags.
+        Regex tags = new Regex("<[^>]*>", RegexCompileFlags.CASELESS);
         return tags.replace(output, -1, 0, "");
     } catch (Error e) {
         debug("Error stripping HTML tags: %s", e.message);