Set up mysql2 as a storage provider

The flags needed to be redefined with a 2 suffix too to work around duplicate declarations.

cmd/trillian_log_server/main.go

@@ -49,6 +49,7 @@ import (
 	_ "github.com/google/trillian/storage/cloudspanner"
 	_ "github.com/google/trillian/storage/crdb"
 	_ "github.com/google/trillian/storage/mysql"
+	_ "github.com/google/trillian/storage/mysql2"
 
 	// Load quota providers
 	_ "github.com/google/trillian/quota/crdbqm"

cmd/trillian_log_signer/main.go

@@ -55,6 +55,7 @@ import (
 	_ "github.com/google/trillian/storage/cloudspanner"
 	_ "github.com/google/trillian/storage/crdb"
 	_ "github.com/google/trillian/storage/mysql"
+	_ "github.com/google/trillian/storage/mysql2"
 
 	// Load quota providers
 	_ "github.com/google/trillian/quota/crdbqm"

storage/mysql2/provider.go

@@ -28,9 +28,9 @@ import (
 )
 
 var (
-	mySQLURI = flag.String("mysql_uri", "test:zaphod@tcp(127.0.0.1:3306)/test", "Connection URI for MySQL database")
-	maxConns = flag.Int("mysql_max_conns", 0, "Maximum connections to the database")
-	maxIdle  = flag.Int("mysql_max_idle_conns", -1, "Maximum idle database connections in the connection pool")
+	mySQLURI = flag.String("mysql2_uri", "test:zaphod@tcp(127.0.0.1:3306)/test", "Connection URI for MySQL database")
+	maxConns = flag.Int("mysql2_max_conns", 0, "Maximum connections to the database")
+	maxIdle  = flag.Int("mysql2_max_idle_conns", -1, "Maximum idle database connections in the connection pool")
 
 	mysqlMu              sync.Mutex
 	mysqlErr             error
@@ -49,7 +49,7 @@ func GetDatabase() (*sql.DB, error) {
 }
 
 func init() {
-	if err := storage.RegisterProvider("mysql", newMySQLStorageProvider); err != nil {
+	if err := storage.RegisterProvider("mysql2", newMySQLStorageProvider); err != nil {
 		klog.Fatalf("Failed to register storage provider mysql: %v", err)
 	}
 }