Fix preferences icon loading in WebUI.

src/webui/www/private/index.html

@@ -94,7 +94,7 @@
                     <a id="decreasePrioButton"><img class="mochaToolButton" title="QBT_TR(Decrease Priority)QBT_TR" src="theme/go-down" alt="QBT_TR(Decrease Priority)QBT_TR" width="24" height="24" onload="fixPNG(this)"/></a>
                     <a id="bottomPrioButton"><img class="mochaToolButton" title="QBT_TR(Minimum Priority)QBT_TR" src="theme/go-bottom" alt="QBT_TR(Minimum Priority)QBT_TR" width="24" height="24" onload="fixPNG(this)"/></a>
                 </span>
-                <a id="preferencesButton" class="divider"><img class="mochaToolButton" title="QBT_TR(Options)QBT_TR" src="theme/preferences-system" alt="QBT_TR(Options)QBT_TR" width="24" height="24" onload="fixPNG(this)"/></a>
+                <a id="preferencesButton" class="divider"><img class="mochaToolButton" title="QBT_TR(Options)QBT_TR" src="theme/configure" alt="QBT_TR(Options)QBT_TR" width="24" height="24" onload="fixPNG(this)"/></a>
             </div>
         </div>
         <div id="pageWrapper">