In order to record a semi-useful filename associated with the key,
this required plumbing the filename all the way through to the remotes'
storeKey and retrieveKeyFile.
Note that there is potential for deadlock here, narrowly avoided.
Suppose the repos are A and B. A sends file foo to B, and at the same
time, B gets file foo from A. So, A locks its upload transfer info file,
and then locks B's download transfer info file. At the same time,
B is taking the two locks in the opposite order. This is only not a
deadlock because the lock code does not wait, and aborts. So one of A or
B's transfers will be aborted and the other transfer will continue.
Whew!
git-annex-shell inannex now returns always 0, 1, or 100 (the last when
it's unclear if content is currently in the index due to it currently being
moved or dropped).
(Actual locking code still not yet written.)
Only one place need to filter the list of remotes for ignored remotes:
keyPossibilities. Make the full list available to everything else.
This allows getting rid of the special case handing for --from and --to
to make ignored remotes not be ignored with those options.
