provider/google: Hook in state migration function
provider/google: Hook in state migration function

As part of Terraform 0.7.1 it was observed in issue #8345 that the state
migration for google_compute_firewall did not appear to be running,
causing a panic when an uninitialized member was read. This commit hooks
up the state migration function (which _was_ independently unit tested
but was not actually in place).

There is currently no good test framework for this, I will address this
issue in a future RFC.

drebes/terraform-provider-google,rosbo/terraform-provider-google,ubschmidt2/terraform-provider-google,hashicorp/terraform-provider-google-beta,terraform-providers/terraform-provider-google,rosbo/terraform-provider-google,ubschmidt2/terraform-provider-google,drebes/terraform-provider-google,selmanj/terraform-provider-google,hashicorp/terraform-provider-google,hashicorp/terraform-provider-google,terraform-providers/terraform-provider-google,drebes/terraform-provider-google,terraform-providers/terraform-provider-google,selmanj/terraform-provider-google,hashicorp/terraform-provider-google-beta,hashicorp/terraform-provider-google,ubschmidt2/terraform-provider-google,drebes/terraform-provider-google,terraform-providers/terraform-provider-google,nickithewatt/terraform-provider-google,rosbo/terraform-provider-google,nickithewatt/terraform-provider-google,hashicorp/terraform-provider-google,hashicorp/terraform-provider-google-beta,terraform-providers/terraform-provider-google,nickithewatt/terraform-provider-google,rosbo/terraform-provider-google,selmanj/terraform-provider-google,hashicorp/terraform-provider-google-beta,ubschmidt2/terraform-provider-google