examples: stop assuming curtin accounts for overhead of logical partitions
Curtin currently has the slightly surprising (to me at least) behaviour
of enlarging an extended partition to account for the overhead that
comes from the fact that logical partitions have to have gaps between
them. I do not intend to preserve this in v2 partitioning (and will
handle this in subiquity) so change the two example files that depend on
this.
Also correct an offset in examples/tests/multipath-reuse.yaml.
The collect script fails on Bionic because lsblk -o PTTYPE does not work
there, so just skip the test there. This was the only failing vmtest
overnight!!
Specifying the offset on a preserved partition is required with a v2
config when the partition does not immediately follow (up to alignment)
the preceding one.
block_meta_v2: change how we invoke sfdisk again, restore partprobe call
It's a bit disappointingly empirical but some multipath vmtests fail
with the current sfdisk arguments with "device busy" type errors. I
think this points to a bug somewhere else but the current partition code
works in this situation so massage things so that the new code does too.
Now we pass --no-tell-kernel to sfdisk, we do need to tell the kernel
about the changes so put back a call to partprobe to do this. This is
actually needed independent of the above change, because it seems sfdisk
with default arguments does not cause the kernel to remove the device
node for a deleted partition!