supply default boxes for known providers
supply default boxes for known providers

This primary benefit is that you can build the appliance without
making any modifications to the source. You can still override the
defaults with VMBOX; the main benefit will be for users who don't want
to know about appliances.

Zimbra/vagrant-provision-zimbra,plobbes/vagrant-provision-zimbra,danchr/vagrant-provision-zimbra,quanah/vagrant-provision-zimbra