Update template for .my.cnf. Add section for mysqladmin, mysqldump

Hi,
About it [pull request #53](https://github.com/phlipper/chef-percona/pull/53). I fixed the same with mysqldump and mysqladmin for munin in past. I didn't use percona yet.
And you can find on [stackoverflow](http://stackoverflow.com/questions/9293042/mysqldump-without-the-password-prompt) questions like this.
I think more pretty will be update template.
What do you think?