Revert "Validate search form of 404 page"

This reverts commit cd7d1246c23d35640a16de6153592c879471f963.

templates/404.html

@@ -20,7 +20,7 @@ Page does not exist at {{ SITENAME|striptags }} blog.
         <p>Sorry, but the page you are looking for cannot be found. It seems that the page you were trying to reach doesn't exist, or may be it has just moved, or it no longer exists.</p>
         <p>The best thing to do is to use the search form or start again from the <a href="{{ SITEURL }}">home page</a>.</p>
         <div class="input-append">
-            <form action="{{ SITEURL }}/search.html" onsubmit="return validateForm()">
+            <form action="{{ SITEURL }}/search.html">
                 <input type="text" class="span12" placeholder="Search" name="q" id="tipue_search_input">
                 <button class="btn" type="button">Search</button>
             </form>