Remove unused code

Author: geofffranks

db/migrations/1472757022_add_placement_tags_to_desired_lrp.go

@@ -58,6 +58,3 @@ func (e *AddPlacementTagsToDesiredLRPs) Up(tx *sql.Tx, logger lager.Logger) erro
 
 	return nil
 }
-
-const alterDesiredLRPAddPlacementTagSQL = `ALTER TABLE desired_lrps
-	ADD COLUMN placement_tags TEXT;`

db/migrations/1481761088_add_max_pid_limit.go

@@ -58,7 +58,3 @@ func (e *AddMaxPidsToDesiredLRPs) Up(tx *sql.Tx, logger lager.Logger) error {
 
 	return nil
 }
-
-const postgresColumnNotExistErr = `"max_pids" does not exist`
-const mysqlColumnNotExistErr = `Unknown column 'max_pids'`
-const checkMaxPidsExistenceSQL = `SELECT count(max_pids) FROM desired_lrps`

models/desired_lrp_test.go

@@ -1589,7 +1589,6 @@ var _ = Describe("DesiredLRPRunInfo", func() {
 	var createdAt = time.Unix(123, 456)
 	var trustedSystemCertificatesPath = "/etc/cf-system-certificates"
 	var httpCheckDef = model_helpers.NewValidHTTPCheckDefinition()
-	const logRateLimitBytesPerSecond = 1024
 	var logRateLimit = &models.LogRateLimit{BytesPerSecond: 1024}
 
 	DescribeTable("Validation",