Kernel Download Fails for Pod Running on Ubuntu 18.04

Hi,

I've been running a bare-metal deployment of Kubernetes through Kubespray, which utilises the ubuntu-nvidia-driver-installer container for GPU-enabled nodes. All of the underlying machines are running Ubuntu 18.04/Bionic, which has been working well so far.

However with the recent release of kernel 4.15.0-44-generic for Ubuntu 18.04, the driver installer init container fails as it cannot locate the linux-headers-4.15.0-44-generic package in the 16.04/Xenial repositories. It looks like at the moment, the Xenial repositories only have 4.15.0-43 available.

For deployments on to 18.04, is it possible to use a container image built from 18.04 as well?

Many thanks.

```
+ NVIDIA_INSTALL_DIR_HOST=/home/kubernetes/bin/nvidia
+ NVIDIA_INSTALL_DIR_CONTAINER=/usr/local/nvidia
++ basename http://us.download.nvidia.com/XFree86/Linux-x86_64/415.27/NVIDIA-Linux-x86_64-415.27.run
+ NVIDIA_INSTALLER_RUNFILE=NVIDIA-Linux-x86_64-415.27.run
+ ROOT_MOUNT_DIR=/root
+ CACHE_FILE=/usr/local/nvidia/.cache
++ uname -r
+ KERNEL_VERSION=4.15.0-44-generic
+ set +x
Checking cached version
Cache file /usr/local/nvidia/.cache found but existing versions didn't match.
Downloading kernel sources...
Get:1 http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get:2 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial-backports InRelease [107 kB]
Get:4 http://archive.ubuntu.com/ubuntu xenial/universe Sources [9802 kB]
Get:5 http://security.ubuntu.com/ubuntu xenial-security InRelease [109 kB]
Get:6 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages [1558 kB]
Get:7 http://security.ubuntu.com/ubuntu xenial-security/universe Sources [118 kB]
Get:8 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages [767 kB]
Get:9 http://archive.ubuntu.com/ubuntu xenial/restricted amd64 Packages [14.1 kB]
Get:10 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages [9827 kB]
Get:11 http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages [176 kB]
Get:12 http://archive.ubuntu.com/ubuntu xenial-updates/universe Sources [305 kB]
Get:13 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [1167 kB]
Get:14 http://archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 Packages [13.1 kB]
Get:15 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [931 kB]
Get:16 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages [19.1 kB]
Get:17 http://security.ubuntu.com/ubuntu xenial-security/restricted amd64 Packages [12.7 kB]
Get:18 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 Packages [529 kB]
Get:19 http://security.ubuntu.com/ubuntu xenial-security/multiverse amd64 Packages [6119 B]
Get:20 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages [7942 B]
Get:21 http://archive.ubuntu.com/ubuntu xenial-backports/universe amd64 Packages [8532 B]
Fetched 25.8 MB in 6s (3702 kB/s)
Reading package lists...
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package linux-headers-4.15.0-44-generic
E: Couldn't find any package by glob 'linux-headers-4.15.0-44-generic'
E: Couldn't find any package by regex 'linux-headers-4.15.0-44-generic'
```