Change partial expenses to pending when reverting available status

Otherwise, i could have an expense that i have set to partial during
development that prevents sqitch to rebase because it is still in use.

revert/available_expense_status.sql

@@ -7,6 +7,7 @@ begin;
 
 set search_path to numerus;
 
+update expense set expense_status = 'pending' where expense_status = 'partial';
 delete from expense_status_i18n where expense_status = 'partial';
 delete from expense_status where expense_status = 'partial';