Changes the mysql charset to utf8

The default charset of the openstack puppet
modules is latin1 this has brought some encoding
problems with glance and heat.
To avoid future problems with the other components
i've changed it to utf8 in all of packstack's template
manifests.

Change-Id: I23a593f9ae0e670f1c3d355bffa2155ed942f017
Fixes: rhbz#1080595, rhbz#1080355