message: gui: move coin control OK to the right
diff: </item>
  <item>
  <widget class="QDialogButtonBox" name="buttonBox">
  - <property name="sizePolicy">
  - <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
  - <horstretch>0</horstretch>
  - <verstretch>0</verstretch>
  - </sizepolicy>
  - </property>
  <property name="orientation">
  <enum>Qt::Horizontal</enum>
  </property>
  