examples: Remove old hcl examples

The hcl frontend was removed a while back. Might as well remove these
examples too.

examples/hcl/graph0.hcl

@@ -1,14 +0,0 @@
-resource "file" "file1" {
-  path = "/tmp/mgmt-hello-world"
-  content = "hello, world"
-  state = "exists"
-  depends_on = ["noop.noop1", "exec.sleep"]
-}
-
-resource "noop" "noop1" {
-  test = "nil"
-}
-
-resource "exec" "sleep" {
- cmd = "sleep 10s"
-}

examples/hcl/graph1.hcl

@@ -1,4 +0,0 @@
-resource "exec" "exec1" {
-  cmd = "cat /tmp/mgmt-hello-world"
-  state =  "present"
-}

examples/hcl/hil.hcl

@@ -1,9 +0,0 @@
-resource "file" "file1" {
-  path = "/tmp/mgmt-hello-world"
-  content = "${exec.sleep.Output}"
-  state = "exists"
-}
-
-resource "exec" "sleep" {
- cmd = "echo hello"
-}