Fix for Bug 250139: New/Edit Address Book Card dialogs shouldn't have buttonpack="center"

r=neil, sr=mscott

mailnews/addrbook/resources/content/abEditCardDialog.xul

@@ -43,7 +43,6 @@
 <dialog xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
   id="abcardWindow"
         onload="OnLoadEditCard()"
-        buttonpack="center"
   ondialogaccept="return EditCardOKButton();">
 
   <stringbundleset id="stringbundleset"/>

mailnews/addrbook/resources/content/abNewCardDialog.xul

@@ -47,7 +47,6 @@
     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
     id="abcardWindow"
     onload="OnLoadNewCard()"
-    buttonpack="center"
     ondialogaccept="return NewCardOKButton();">
 
   <stringbundleset id="stringbundleset"/>