Add DB Create step on "Install and configure (Ubuntu) in glance"

[Youhei Tooyama]

This bug tracker is for errors with the documentation, use the following as a template and remove or add fields as you see fit. Convert [ ] into [x] to check boxes:

- [X] This doc is inaccurate in this way: ______
- [ ] This is a doc addition request.
- [ ] I have a fix to the document that I can paste below including example: input and output.

Please add this step.

2. Create the glance database

MariaDB [(none)]> CREATE DATABASE glance;

3. Grant proper access to the glance database:

MariaDB [(none)]> GRANT ALL PRIVILEGES ON glance.* TO 'glance'@'localhost' \
IDENTIFIED BY 'GLANCE_DBPASS';
MariaDB [(none)]> GRANT ALL PRIVILEGES ON glance.* TO 'glance'@'%' \
IDENTIFIED BY 'GLANCE_DBPASS';

Thanks!

-----------------------------------
Release: 15.0.0.0rc2.dev25 on 'Wed Aug 23 03:33:04 2017, commit 9820166'
SHA: 982016670fe908e5d7026714b115e63b7c31b46b
Source: https://git.openstack.org/cgit/openstack/glance/tree/doc/source/install/install-ubuntu.rst
URL: https://docs.openstack.org/glance/pike/install/install-ubuntu.html