[FIX] openerp: quote read_group SQL query for case sensitive tables

In SQL, if there is no quote around the table/field, the result will
be returned as case insensitive.

This was causing a bug in the kanban view which was not displaying
the records because x_AA_count was named x_aa_count.

openerp/models.py

@@ -2127,7 +2127,7 @@ class BaseModel(object):
         prefix_term = lambda prefix, term: ('%s %s' % (prefix, term)) if term else ''
 
         query = """
-            SELECT min(%(table)s.id) AS id, count(%(table)s.id) AS %(count_field)s %(extra_fields)s
+            SELECT min("%(table)s".id) AS id, count("%(table)s".id) AS "%(count_field)s" %(extra_fields)s
             FROM %(from)s
             %(where)s
             %(groupby)s