[income-gst-statement] bugfix must not translate option names

This bug would cause report crash for localized builds because the
option names were localized and could never be retrieved from the
options tree.

gnucash/report/standard-reports/income-gst-statement.scm

@@ -147,8 +147,8 @@ for taxes paid on expenses, and type LIABILITY for taxes collected on sales.")
        (accounts-tax-paid      (filter (lambda (acc) (eq? (xaccAccountGetType acc) ACCT-TYPE-ASSET))     tax-accounts))
        (accounts-sales         (filter (lambda (acc) (eq? (xaccAccountGetType acc) ACCT-TYPE-INCOME))    accounts))
        (accounts-purchases     (filter (lambda (acc) (eq? (xaccAccountGetType acc) ACCT-TYPE-EXPENSE))   accounts))
-       (common-currency (and (opt-val gnc:pagename-general (_ "Common Currency"))             ; if a common currency was specified,
-                             (opt-val gnc:pagename-general (_ "Report's currency"))))         ; use it
+       (common-currency (and (opt-val gnc:pagename-general "Common Currency")             ; if a common currency was specified,
+                             (opt-val gnc:pagename-general "Report's currency")))         ; use it
        (split-date (lambda (s) (xaccTransGetDate (xaccSplitGetParent s))))
        (split-currency (lambda (s) (xaccAccountGetCommodity (xaccSplitGetAccount s))))
        (split-adder (lambda (split accountlist)