Drop useless spaces in button label

It is problematic when it comes to i18n and is useless here.

picard/ui/ui_cdlookup.py

@@ -66,6 +66,6 @@ class Ui_Dialog(object):
         Dialog.setWindowTitle(_("CD Lookup"))
         self.label.setText(_("The following releases on MusicBrainz match the CD:"))
         self.ok_button.setText(_("OK"))
-        self.lookup_button.setText(_("    Lookup manually    "))
+        self.lookup_button.setText(_("Lookup manually"))
         self.cancel_button.setText(_("Cancel"))
 

ui/cdlookup.ui

@@ -68,7 +68,7 @@
      <item>
       <widget class="QPushButton" name="lookup_button">
        <property name="text">
-        <string>    Lookup manually    </string>
+        <string>Lookup manually</string>
        </property>
       </widget>
      </item>