Low: mysql: Refactoring mysql logic into common library that can be shared with galera agent

Galera is just mysql with some fancy wrappers. I have refactored
the mysql agent so we can create a new galera agent without
having to introduce a bunch of code overlap with the mysql agent.
All the code that can be shared between the mysql agent and galera
has been moved to mysql-common.sh
High: galera: Introduces galera resource-agent
Low: galera: readme text describing the galera agent
High: galera: wait for db sync during promote
Low: galera: handle large db commit value comparisons
Low: ocf-shellfunctions: handle local nodename when version has distro postfix
Merge pull request #449 from davidvossel/galera-agent

Galera resource-agent