Replace all []*Foo by []Foo in sql db return values

- Implement SlicePtrsToSlice and use it in all `meddler.QueryAll` sql db functions to always return []Foo instead of []*Foo

db/l2db/l2db.go

@@ -7,6 +7,7 @@ import (
 
 	ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/hermeznetwork/hermez-node/db"
 	"github.com/hermeznetwork/hermez-node/log"
 	"github.com/iden3/go-iden3-crypto/babyjub"
 	"github.com/jmoiron/sqlx"
@@ -134,14 +135,14 @@ func (l2db *L2DB) GetTx(txID common.TxID) (*common.PoolL2Tx, error) {
 }
 
 // GetPendingTxs return all the pending txs of the L2DB, that have a non NULL AbsoluteFee
-func (l2db *L2DB) GetPendingTxs() ([]*common.PoolL2Tx, error) {
+func (l2db *L2DB) GetPendingTxs() ([]common.PoolL2Tx, error) {
 	var txs []*common.PoolL2Tx
 	err := meddler.QueryAll(
 		l2db.db, &txs,
 		selectPoolTx+"WHERE state = $1 AND token.usd IS NOT NULL",
 		common.PoolL2TxStatePending,
 	)
-	return txs, err
+	return db.SlicePtrsToSlice(txs).([]common.PoolL2Tx), err
 }
 
 // StartForging updates the state of the transactions that will begin the forging process.

db/l2db/l2db_test.go

@@ -111,8 +111,8 @@ func TestGetPending(t *testing.T) {
 	fetchedTxs, err := l2DB.GetPendingTxs()
 	assert.NoError(t, err)
 	assert.Equal(t, len(pendingTxs), len(fetchedTxs))
-	for i, fetchedTx := range fetchedTxs {
-		assertTx(t, pendingTxs[i], fetchedTx)
+	for i := range fetchedTxs {
+		assertTx(t, pendingTxs[i], &fetchedTxs[i])
 	}
 }