added compute keypair

datasources.tf

 data "openstack_networking_network_v2" "public-network" {
   name = "${var.public-network-name}"
 }
+
+data "openstack_compute_keypair_v2" "keypair" {
+  name       = "${var.os-gen-keypair}"
+  public_key = "${file("~/.ssh/id_rsa.pub")}"
+  private_key = "${file("~/.ssh/id_rsa")}"
+}
+