Workbench shows branch databases when issuing `SHOW DATABASES` query

[timsehn]

Both Dolthub and local dolt do not show it. Not even sure how it's getting there.

[liuliu-dev]

It seems this behavior is not specific to the Dolt Workbench.

When start a dolt server using dolt sql-server and connect to it with a mysql client (mysql -h localhost -P 3306 -u root), the mysql client also shows branch databases.

repro:

1. in a dolt db:

dolt sql-server

2. connect to it with a mysql client:

 mysql -h localhost -P 3306 -u root

3. change database to db/main and then run show databases:

mysql> use test1/main;
Database changed
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| test1              |
| test1/main         |
+--------------------+
4 rows in set (0.00 sec)