satellite/satellitedb: drop _gob columns

This concludes the saga that began with commit c053bdb, migrating away
from using gob-encoded big.Float values in the database to using
integers with an implied number of decimal places.

Nothing is using or accessing or expecting the _gob columns to exist
anymore. The transition code and the migration chore are gone. All that
remains is to drop the columns.

Change-Id: I9b15ee52f7781510a6dc91cf7c54f7f9022b1210

satellite/satellitedb/migrate.go

@@ -2079,6 +2079,15 @@ func (db *satelliteDB) PostgresMigration() *migrate.Migration {
 					`ALTER TABLE users ADD COLUMN signup_captcha double precision;`,
 				},
 			},
+			{
+				DB:          &db.migrationDB,
+				Description: "Drop now-unused gob-encoded columns",
+				Version:     211,
+				Action: migrate.SQL{
+					`ALTER TABLE coinpayments_transactions DROP COLUMN amount_gob, DROP COLUMN received_gob;`,
+					`ALTER TABLE stripecoinpayments_tx_conversion_rates DROP COLUMN rate_gob;`,
+				},
+			},
 			// NB: after updating testdata in `testdata`, run
 			//     `go generate` to update `migratez.go`.
 		},

satellite/satellitedb/migratez.go

@@ -13,7 +13,7 @@ func (db *satelliteDB) testMigration() *migrate.Migration {
 			{
 				DB:          &db.migrationDB,
 				Description: "Testing setup",
-				Version:     210,
+				Version:     211,
 				Action: migrate.SQL{`-- AUTOGENERATED BY storj.io/dbx
 -- DO NOT EDIT
 CREATE TABLE accounting_rollups (
@@ -93,9 +93,7 @@ CREATE TABLE coinpayments_transactions (
 	id text NOT NULL,
 	user_id bytea NOT NULL,
 	address text NOT NULL,
-	amount_gob bytea,
 	amount_numeric int8 NOT NULL,
-	received_gob bytea,
 	received_numeric int8 NOT NULL,
 	status integer NOT NULL,
 	key text NOT NULL,
@@ -458,7 +456,6 @@ CREATE TABLE stripecoinpayments_invoice_project_records (
 );
 CREATE TABLE stripecoinpayments_tx_conversion_rates (
 	tx_id text NOT NULL,
-	rate_gob bytea,
 	rate_numeric double precision NOT NULL,
 	created_at timestamp with time zone NOT NULL,
 	PRIMARY KEY ( tx_id )