ubuntu-cpc: make /etc/fstab consistent with other ubuntu images

Modify the mount options in fstab to make the Cloud images consistent
with the default we have elsewhere.

LP: #1902103
LP: #1881006

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.715) hirsute; urgency=medium
+
+  * ubuntu-cpc: change mount options in fstab to be align with defaults
+    (LP: #1902103, LP: #1881006)
+
+ -- Gauthier <gauthier.jolly@canonical.com>  Tue, 02 Mar 2021 14:17:39 +0000
+
 livecd-rootfs (2.714) hirsute; urgency=medium
 
   * Suppress cloud-init output during boot of live server ISO.

live-build/ubuntu-cpc/hooks.d/base/disk-image-uefi.binary

@@ -94,7 +94,7 @@ create_and_mount_uefi_partition() {
     mount "${uefi_dev}" "$mountpoint"/boot/efi
 
     cat << EOF >> "mountpoint/etc/fstab"
-LABEL=UEFI	/boot/efi	vfat	defaults	0 1
+LABEL=UEFI	/boot/efi	vfat	umask=0077	0 1
 EOF
 }
 

live-build/ubuntu-cpc/hooks.d/chroot/999-cpc-fixes.chroot

@@ -72,7 +72,7 @@ if [ -n "${root_fs_label}" ]; then
    sed -i "s,^[^#${bl}]*\([${bl}]*/[${bl}].*\),${lstr}\1," "${rootd}/etc/fstab"
 fi
 cat > /etc/fstab << EOM
-LABEL=cloudimg-rootfs	/	 ext4	defaults	0 1
+LABEL=cloudimg-rootfs	/	 ext4	discard,errors=remount-ro	0 1
 EOM
 
 # for quantal and newer, add /etc/overlayroot.local.conf