ostree admin deploy: Add --no-prune option

[wmanley]

If you want cleanup, but don't want to prune the repo. Pruning can be quite expensive so ostree admin deploy can be much faster without pruning.

On the NVidia Tegra TK1 pruning can take 20s, even when there is nothing to delete.

TODO:

• test it

[cgwalters]

I only quickly glanced at this so far, but I'm a bit uncertain as to the need for the flag and the option? Can't we just port the cli to use ostree_sysroot_simple_write_deployment_with_options() from a5d5333 ?

[wmanley]

Can't we just port the cli to use ostree_sysroot_simple_write_deployment_with_options() from a5d5333 ?

I had a go at that and we end up duplicating the logic from ostree_sysroot_simple_write_deployment that comes up with the list of new deployments. Instead I have just passed the NO_CLEAN flag and done the cleaning ourselves in ot_admin_builtin_deploy. The only theoretical difference is that now the cleaning will happen with a read-write /boot rather than a read-only one.

I haven't tested it yet though...

[cgwalters]

Going back over this I'm uncertain why we don't just forcibly do prepare_cleanup() before starting to write deployments or so. But that'd require some more tricky investigation.

I'm not worried about the read/write vs ro /boot yet, that logic is going to need a lot more work that should end up going along with #1265

So this LGTM.

@rh-atomic-bot r+ 1731f42

[rh-atomic-bot]

⌛ Testing commit 1731f42 with merge 2098f75...

[rh-atomic-bot]

☀️ Test successful - status-atomicjenkins
Approved by: cgwalters
Pushing 2098f75 to master...