hack/get-terraform: Remove obsolete script

Now that we're vendoring Terraform, we no longer need a script to pull
down pre-compiled binaries.

I've also reworded the 'create cluster' description in overview.md to
be more generic.  See 0c3d8658 (asset/cluster: clean up logging
messages, 2018-12-07, #840) for similar changes to another location.

Author: wking

README.md

@@ -22,13 +22,6 @@ This will create `bin/openshift-install`. This binary can then be invoked to cre
 bin/openshift-install create cluster
 ```
 
-The installer requires the terraform binary either alongside openshift-install or in `$PATH`.
-If you don't have [terraform](https://www.terraform.io/), run the following to create `bin/terraform`:
-
-```sh
-hack/get-terraform.sh
-```
-
 The installer will show a series of prompts for user-specific information and use reasonable defaults for everything else. In non-interactive contexts, prompts can be bypassed by providing appropriately-named environment variables. Refer to the [user documentation](docs/user) for more information.
 
 ### Connect to the cluster

docs/user/overview.md

@@ -38,7 +38,7 @@ The following targets can be created by the installer:
 - `install-config` - The install config contains the main parameters for the installation process. This configuration provides the user with more options than the interactive prompts and comes pre-populated with default values.
 - `manifests` - This target outputs all of the Kubernetes manifests that will be installed on the cluster.
 - `ignition-configs` - These are the three Ignition Configs for the bootstrap, master, and worker machines.
-- `cluster` - This target provisions the cluster by invoking a locally-installed Terraform.
+- `cluster` - This target provisions the cluster and its associated infrastructure.
 
 The following targets can be destroyed by the installer:
 

hack/get-terraform.sh

@@ -4,7 +4,7 @@
 FROM openshift/origin-release:golang-1.10 AS build
 WORKDIR /go/src/github.com/openshift/installer
 COPY . .
-RUN hack/build.sh && hack/get-terraform.sh
+RUN hack/build.sh
 
 
 FROM centos:7

images/installer/Dockerfile.ci

@@ -3,7 +3,7 @@
 FROM openshift/origin-release:golang-1.10 AS build
 WORKDIR /go/src/github.com/openshift/installer
 COPY . .
-RUN hack/build.sh && hack/get-terraform.sh
+RUN hack/build.sh
 
 FROM centos:7
 COPY --from=build /go/src/github.com/openshift/installer/bin/openshift-install /bin/openshift-install