Update preferences.ui as per recent QtDesigner

No changes to the form - .ui file changes only because QtDesigner
generates the .ui file differently

client/preferences.ui

@@ -1,3 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <ui version="4.0">
  <class>Preferences</class>
  <widget class="QDialog" name="Preferences">
@@ -13,7 +14,8 @@
    <string>Preferences</string>
   </property>
   <property name="windowIcon">
-   <iconset resource="ostinato.qrc" >:/icons/preferences.png</iconset>
+   <iconset resource="ostinato.qrc">
+    <normaloff>:/icons/preferences.png</normaloff>:/icons/preferences.png</iconset>
   </property>
   <layout class="QVBoxLayout">
    <item>
@@ -150,7 +152,7 @@
         <property name="orientation">
          <enum>Qt::Vertical</enum>
         </property>
-        <property name="sizeHint" >
+        <property name="sizeHint" stdset="0">
          <size>
           <width>21</width>
           <height>61</height>
@@ -167,7 +169,7 @@
       <enum>Qt::Horizontal</enum>
      </property>
      <property name="standardButtons">
-      <set>QDialogButtonBox::Cancel|QDialogButtonBox::NoButton|QDialogButtonBox::Ok</set>
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
      </property>
     </widget>
    </item>