updated README.md to Swift-On-File

Signed-off-by: Thiago da Silva <thiago@redhat.com>
added new support filesystem section

Also, called out the fact that the quick start guide
focus on glusterfs

Signed-off-by: Thiago da Silva <thiago@redhat.com>
Merge pull request #8 from thiagol11/update_readme

updated README.md to Swift-On-File