Changes to support refactor in frappe pg-poc branch (#15287)

* Remove quotes from sql to make it compatible with postgres as well

* Fix queries
- Replace mysql specifc queries with standard ones

* Make repo URL chages to test pg-poc

* Add root passowrd to test site config

* Fix quotes issue

* Remove debug flag from a pricing rule query

* Remove python 3.6 version from travis.yml

* Fix improper query issue

* Fix incorrect query

* Fix a query

- This fix need to be changed when we will  start supporting postgres
since date_format is not supported by postgres

* Get price list map as dict

* Convert price_list_currency_map to dict

erpnext/controllers/buying_controller.py

@@ -746,7 +746,7 @@ def validate_item_type(doc, fieldname, message):
 	if not items:
 		return
 
-	item_list = ", ".join(["'%s'" % frappe.db.escape(d) for d in items])
+	item_list = ", ".join(["%s" % frappe.db.escape(d) for d in items])
 
 	invalid_items = [d[0] for d in frappe.db.sql("""
 		select item_code from tabItem where name in ({0}) and {1}=0