fix problem with folder permissions and imap acl r/sr=sspitzer 170597

mailnews/imap/src/nsImapMailFolder.cpp

@@ -5248,9 +5248,6 @@ PRBool nsMsgIMAPFolderACL::SetFolderRightsForUser(const char *userName, const ch
 
 const char *nsMsgIMAPFolderACL::GetRightsStringForUser(const char *inUserName)
 {
-  if (!inUserName)
-    return nsnull;
-
   nsXPIDLCString userName;
   userName.Assign(inUserName);
   if (!userName.Length())