Increase boot delay further

Author: ripleymj

packer/ubuntu-kvm.json

@@ -55,7 +55,7 @@
       "vm_name": "image.qcow2",
       "net_device": "virtio-net",
       "disk_interface": "virtio",
-      "boot_wait": "20s",
+      "boot_wait": "25s",
       "boot_command": [
         "c<wait><wait>",
         "linux /casper/vmlinuz",