I have successfully installed Odoo 8.0 from the nightly downloads using the latest tar.gz file odoo_8.0rc1-latest.tar.gz (from http://nightly.odoo.com/8.0/nightly/deb/). I am able to get the opening screen using the URL http://xx.xx.xx.xx/8069.
After downloading and unzipping the tar.dz file, I copied the openerp-server.conf from /odoo/debian folder file to /etc folder. I changed the admin Password in the openerp-server.conf file from the default password 'admin' to 'myownpassword'. Saved the file and restarted the openerp server.
When I tried creating a database through UI using the odoo's default password 'admin' it is still allowing me to do so. When I delete the database using this default password 'admin', it is deleting without asking for a correct password.
I would appreciate for any help changing the master password.
I think your database password is "admin", do change it to your 'myownpassword' [same as odoo master password]