libutil: tidy Sync and fix its move constructor

There was a previously-unused move constructor that just called abort,
which makes no sense since it ought to just be `= delete` if you don't
want one (commit history says it was Eelco doing an optimistic
performance optimisation in 2016, so it probably would not pass review
today).

However, a Lock has some great reasons to be moved! You might need to
unlock it early, for instance, or give it to someone else. So we change
the move constructor to instead hollow out the moved-from object and
make it unusable.

Change-Id: Iff2a4c2f7ebd0a558c4866d4dfe526bc8558bed7

0 files changed, 0 insertions, 0 deletions