Updates for Ansible Galaxy 2.0.

Merge pull request geerlingguy#9 from JorisVanEijden/master

PR geerlingguy#9: Support maxmemory.

Merge pull request geerlingguy#8 from danielshiplett/master

PR geerlingguy#8: Make PID file name dynamic based on daemon name.

Fixes geerlingguy#6: Remove hash-max-* to make config work with Redis…

… > 2.6.

Fixes geerlingguy#5: vm-enabled no startup error.

Document Redis configuration variables.

More Travis debugging.

Add EL 7 to supported platforms.

Removed unused vars file.