ASM-1331 run puppet agent as Administrator on windows

The default installation account does not have permission to access
network resources. As a result the citrix install fails because the
installer files are downloaded from the appliance's SMB share.

For more details see
http://docs.puppetlabs.com/windows/installing.html#agent-account
Merge pull request #8 from gavin-scott/asm-1331

ASM-1331 run puppet agent as Administrator on windows