Add check for puppet rpm before trying to install

This fixes an issue where subsequent tests will fail when the RS_PROVISION=no and RS_DESTROY=no flag is set for centos. The error is caused by attempting to install the puppet rpm on a machine that already has the puppet rpm installed.
update to install package using yum instead of rpm
Merge pull request #445 from Phil0xF7/fix_multiple_rpm_install

Add check for puppet rpm before trying to install