fix crash on invalid lock in litmus test

[gstrauss]

fix crash on invalid lock in litmus test

This commit is from 2016 for an issue I ran into with litmus when I was bringing lighttpd mod_webdav up to RFC4918. I do not have immediate example of the item it fixes, but the change is only a couple lines and the commit message describes the issues it fixes.

If there are questions, please ask and I'll add more details.

Similar in age to notroj/litmus#6

[notroj]

Do you know how it happened that a lock ended up in the store without a valid URI? I'm not necessarily against the patch but I'm wondering if it is something that should have been caught and treated as an error earlier, rather than crashing here.

[gstrauss]

Do you know how it happened that a lock ended up in the store without a valid URI?

Back in 2016, I was using litmus (thank you!) to improve a then-non-compliant (with RFC4918) WebDAV implementation. I suppose I could copy out an old version from 2015 and see if I can reproduce this. I'll need to find some time to do so, but intend to update this when I do, hopefully later this month.