TT#82317 save contract balance delta for re-rating

this cdr tag will be used to persist the compressed
delta datastructure for contract_balance records.

additional tablespace consumption is minimal: there
will be only one string value (~20chars on average)
required per cdr.

Change-Id: I32557443df2efa7381c85ddfb8c380c8df02df5e

db_scripts/diff/15607.down

@@ -0,0 +1,7 @@
+USE accounting;
+SET autocommit=0;
+
+DELETE FROM cdr_tag WHERE type = 'balance_delta';
+
+COMMIT;
+

db_scripts/diff/15607.up

@@ -0,0 +1,6 @@
+USE accounting;
+SET autocommit=0;
+
+INSERT INTO cdr_tag SET id = null, type = 'balance_delta';
+
+COMMIT;