[minor] fixes for patch set_currency_field_precision (#3253)

frappe/patches.txt

@@ -179,7 +179,7 @@ execute:frappe.db.sql("update `tabDesktop Icon` set type='list' where _doctype='
 frappe.patches.v8_0.fix_non_english_desktop_icons # 2017-04-12
 frappe.patches.v8_0.set_doctype_values_in_custom_role
 frappe.patches.v8_0.install_new_build_system_requirements
-frappe.patches.v8_0.set_currency_field_precision
+frappe.patches.v8_0.set_currency_field_precision	# 2017-05-09
 frappe.patches.v8_0.rename_print_to_printing
 frappe.patches.v7_1.disabled_print_settings_for_custom_print_format
 frappe.patches.v8_0.update_desktop_icons

frappe/patches/v8_0/set_currency_field_precision.py

@@ -6,6 +6,7 @@ import frappe
 from frappe.utils import get_number_format_info
 
 def execute():
+	frappe.reload_doc('core', 'doctype', 'system_settings')
 	if not frappe.db.get_value("System Settings", None, "currency_precision"):
 		default_currency = frappe.db.get_default("currency")
 		number_format = frappe.db.get_value("Currency", default_currency, "number_format") \