Add note about overwriting destination file
Add note about overwriting destination file

Closes #4905

grubernaut/packer,dave2/packer,ricardclau/packer,mitchellh/packer,paulmey/packer,timsutton/packer,mkuzmin/packer,mitchellh/packer,mkuzmin/packer,grubernaut/packer,pecigonzalo/packer,tas50/packer,youhong316/packer,bryson/packer,bryson/packer,ricardclau/packer,grubernaut/packer,tb3088/packer,rnaveiras/packer,tas50/packer,bryson/packer,dave2/packer,pecigonzalo/packer,rnaveiras/packer,mkuzmin/packer,paulmey/packer,youhong316/packer,dave2/packer,ricardclau/packer,pecigonzalo/packer,timsutton/packer,tas50/packer,hashicorp/packer,dave2/packer,dave2/packer,tb3088/packer,bryson/packer,tb3088/packer,mkuzmin/packer,timsutton/packer,rnaveiras/packer,hashicorp/packer,youhong316/packer,ricardclau/packer,youhong316/packer,ricardclau/packer,paulmey/packer,rnaveiras/packer,tas50/packer,rnaveiras/packer,tas50/packer,paulmey/packer,dave2/packer,tb3088/packer,grubernaut/packer,grubernaut/packer,timsutton/packer,rnaveiras/packer,timsutton/packer,paulmey/packer,pecigonzalo/packer,mitchellh/packer,paulmey/packer,mkuzmin/packer,youhong316/packer,ricardclau/packer,hashicorp/packer,tb3088/packer,youhong316/packer,tb3088/packer,bryson/packer,mkuzmin/packer,timsutton/packer,hashicorp/packer,mitchellh/packer,tas50/packer,grubernaut/packer,bryson/packer,mitchellh/packer