Allow nodepool standalone puppet install

Installing nodepool standalone has this error:
 Could not find dependency Class[Pip] for Exec[install_nodepool] at
 /root/config/modules/nodepool/manifests/init.pp:90

Add the missing include pip statement.

Change-Id: Id30814eb1788e7b7eb533794a26c231000e9b41c
Merge "Allow nodepool standalone puppet install"