added validation and clear fields for Apply Rule On Other

(cherry picked from commit ebbbc85fc0f9aa418163f8344d3a234ecbe08488)
diff --git a/erpnext/accounts/doctype/pricing_rule/pricing_rule.py b/erpnext/accounts/doctype/pricing_rule/pricing_rule.py
index ef1f4e6..ead300e 100644
--- a/erpnext/accounts/doctype/pricing_rule/pricing_rule.py
+++ b/erpnext/accounts/doctype/pricing_rule/pricing_rule.py
@@ -17,6 +17,8 @@
 apply_on_dict = {"Item Code": "items",
 	"Item Group": "item_groups", "Brand": "brands"}
 
+other_fields = ["other_item_code", "other_item_group", "other_brand"]
+
 class PricingRule(Document):
 	def validate(self):
 		self.validate_mandatory()
@@ -47,6 +49,13 @@
 		if tocheck and not self.get(tocheck):
 			throw(_("{0} is required").format(self.meta.get_label(tocheck)), frappe.MandatoryError)
 
+		if self.apply_rule_on_other:
+			o_field = 'other_' + frappe.scrub(self.apply_rule_on_other)
+			if not self.get(o_field) and o_field in other_fields:
+				frappe.throw(_("For the 'Apply Rule On Other' condition the field {0} is mandatory")
+					.format(frappe.bold(self.apply_rule_on_other)))
+
+
 		if self.price_or_product_discount == 'Price' and not self.rate_or_discount:
 			throw(_("Rate or Discount is required for the price discount."), frappe.MandatoryError)
 
@@ -93,6 +102,14 @@
 		if self.mixed_conditions and self.get("same_item"):
 			self.same_item = 0
 
+		apply_rule_on_other = frappe.scrub(self.apply_rule_on_other or "")
+
+		cleanup_other_fields = (other_fields if not apply_rule_on_other
+			else [o_field for o_field in other_fields if o_field != 'other_' + apply_rule_on_other])
+
+		for other_field in cleanup_other_fields:
+			self.set(other_field, None)
+
 	def validate_rate_or_discount(self):
 		for field in ["Rate"]:
 			if flt(self.get(frappe.scrub(field))) < 0: