The current logging of failures for retrieve requests was attempting to retrieve the
list after the object was removed. The failures list has been moved to another log line,
similar to how it is done with archive requests.

Created initial (incomplete) logging of timings for generic popping from container.

Fixed missing variable initialization.
Added queue trimming.
Moved function from header to cpp.

The unit test is disabled as it does not pass yet.
Templated some structures to reflect imperfect similarities between inserting and popping.

Done.

The WrongPreviousOwner exception has been moved out from archive and retrieve requests to have more generic code.

Exits from Init() with exit(1) in case of failure instead of returning
false, as a temporary workaround until the following XRootD bug is
fixed:
https://github.com/xrootd/xrootd/issues/751

Done

Created conrresponding unit test.

Added more information to ContainerTraits<ArchiveQueue> to avoid querying the archive request object.

Upgraded to EOS 4.2.24-20180614121622git0cf4285 which has the fix for compactions slowing opens for read