Update adminpages.php

Missing gettext for menu title causing the title not to be translated correctly.
Merge pull request #128 from Askelon/patch-1

Update adminpages.php
Now including expiration text in text that is updated when a discount code is used. (Thanks, John Zeiger)
Fixed check for subscription_transaction_id in readonly fields array.
Merge branch 'dev' into v2.0

Conflicts:
	readme.txt
trimming trailing spaces.