GCE dev-machine steps need an update

[arun-gupta]

Here are the issues with dev-machine-setup for GCP:

• In first step, a space before and after = breaks the copy/paste

• gcloud compute disks create command fails without explicitly specifying the project. The updated command is:

  gcloud compute disks create ${FC_VDISK}   --image-project ubuntu-os-cloud --image-family ubuntu-1804-lts --project ${FC_PROJECT}
  

• Updated command fails with the following error:

  gcloud compute disks create ${FC_VDISK}   --image-project ubuntu-os-cloud --image-family 
  ubuntu-1804-lts --project ${FC_PROJECT}
  API [compute.googleapis.com] not enabled on project [175661354881]. 
  Would you like to enable and retry (this will take a few minutes)? 
  (y/N)?  yes
  
  Enabling service [compute.googleapis.com] on project [175661354881]...
  ERROR: (gcloud.compute.disks.create) FAILED_PRECONDITION: Operation does not satisfy the following requirements: billing-enabled {Billing must be enabled for activation of service '' in project 'arun-firecracker' to proceed., https://console.developers.google.com/project/arun-firecracker/settings}
  

  Billing account has to explicitly associated by following the instructions in the error message.

• In step 3, a space before and after = breaks the copy/paste

[dianpopa]

The aforementioned problems were fixed by #2502.