Bug 308988 support delegated use of imap shared folders - file I missed from initial check-in - sorry

p=me r=mnyromyr sr=bienvenu

suite/locales/en-US/chrome/mailnews/msgHdrViewOverlay.dtd

@@ -37,6 +37,7 @@
 
 <!ENTITY toField.label "To: ">
 <!ENTITY fromField.label "From: ">
+<!ENTITY senderField.label "Sender: ">
 <!ENTITY organizationField.label "Organization: ">
 <!ENTITY replyToField.label "Reply-To: ">