Merge lp:~ltrager/maas-images/bionic_bootloaders into lp:maas-images

[Lee Trager]

Switch boot loaders to pull from Bionic instead of Xenial

The MAAS bootloaders stream should contain bootloaders from the latest LTS.
Now that Bionic 18.04.1 is out it is safe to switch.

Test stream: http://162.213.35.187/bionic_bootloaders/

Version changes

    Package Xenial Bonic
grub2-signed(uefi-amd64) 1.66.18+2.02~beta2-36ubuntu3.18 1.93.2+2.02-2ubuntu8.1
shim-signed(uefi-amd64) 1.33.1~16.04.1+13-0ubuntu2 1.34.9.2+13-0ubuntu2
grub2(uefi-arm64) 2.02~beta2-36ubuntu3.18 2.02-2ubuntu8.1
grub2(open-firmware-ppc64el) 2.02~beta2-36ubuntu3.18 2.02-2ubuntu8.1
syslinux(pxe-i386,amd64, powernv-ppc64) 3:6.03+dfsg-11ubuntu1 3:6.03+dfsg1-2

[Newell Jensen (newell-jensen)]

LGTM

review: Approve

=== modified file 'conf/bootloaders.yaml'
--- conf/bootloaders.yaml	2018-07-17 19:01:23 +0000
+++ conf/bootloaders.yaml	2018-07-19 07:54:01 +0000
@@ -9,7 +9,7 @@
    arch: i386
    arches: i386,amd64
    archive: http://archive.ubuntu.com/ubuntu
-   release: xenial
+   release: bionic
    os: pxelinux
    files:
     - usr/lib/PXELINUX/pxelinux.0
@@ -22,7 +22,7 @@
    arch: amd64
    arches: amd64
    archive: http://archive.ubuntu.com/ubuntu
-   release: xenial
+   release: bionic
    os: grub-efi-signed
    files:
     - usr/lib/shim/shimx64.efi.signed, bootx64.efi
@@ -33,7 +33,7 @@
    arch: arm64
    arches: arm64
    archive: http://ports.ubuntu.com
-   release: xenial
+   release: bionic
    os: grub-efi
    files:
     - usr/lib/grub/arm64-efi/
@@ -54,7 +54,7 @@
    arch: ppc64el
    arches: ppc64el,ppc64
    archive: http://ports.ubuntu.com
-   release: xenial
+   release: bionic
    os: grub-ieee1275
    files:
     - usr/lib/grub/powerpc-ieee1275/