Proceed all successful reports asynchronously and periodically check
and clear statuses if they have finished.
In the end of session do the check/flush for all reports in the
successful reports queue.

Switch from synchronous rados remove to async aio_remove in
case of zero size object in BackendRados::AsyncUpdater

As those fuctions are usually called in a tight loop at the end of the session or in the garbage collector,
they tend to unlock and relock the queues immediately, and sitting on the lock for a long time in practice.
The added sleep will increase the odds of other processing slipping in between the unlock and the lock.

The ping() and queueRetrieve() timings are of interest, so commit now.
The rest of the timings will follow.

Use precision .00 for Mbytes. Move library name to the front.

This led to failure to requeue non-handled jobs at the end of a tape session (and leave them
to garbage collection.
Also added timings.

Removed all instances of RetrieveMount::getNextJob() and siblings.
Fixed incomplete deserialization of archive file in RetrieveRequest::asyncUpdateOwner().

Done.

Changed reporting to the Catalog with a batch of written files.
Changed synchronous reporting to the backend job by job to the
asynchronous reporting for batch of jobs.
Changed synchronous reporting to the EOS mgm to the asynchronous
reporting.

This new version locks the queues for less time.
Fixed a bug where the wrong lock (shared and not exclusive) was taken when removing empty queues
from the root entry.
Improved multiple iterations retrying (we can now retry on a new queue if one gets contructed
in the meantime.

This makes the system tests faster on HDD backed systems as mhvtl is an heavy user of fsync.

Fsync cost can go up to 100ms on HDD (+vm + hyperV).

This is a temporary solution before parallel request updating is deployed in RetrieveMount::getNextJobBatch().

Cleanup/reorder/rename for some fields.

Some cases of operations taking over a minute were seen practice.

The queue size division by the number of existing mount is only valid for archive mounts
where the queue is shared by each mount. In the case of retrieves, the criteria should be considered
vid by vid and the number of exiting mounts should not matter.

This commit fixes the following error encountered by the
Continuous Integration system and discovered and
reported by Eric:

Config Falling back to using libXrdCtaOfs.so
Plugin /lib64/libXrdCtaOfs.so: undefined symbol: _ZN3cta13xroot_plugins16XrdCtaFilesystem5FSctlEiR11XrdSfsFSctlR13XrdOucErrInfoPK12XrdSecEntity fslib libXrdCtaOfs.so
Config Unable to load fslib plugin libXrdCtaOfs.so
170804 02:37:03 558 XrootdConfig: Unable to create file system object via libXrdCtaOfs.so
170804 02:37:03 558 XrootdConfig: Unable to load file system.
------ xrootd protocol initialization failed.

The origin of the problem is the following commit that
completed removed the implemention of the
XrdCtaFilesystem::FSctl() method:

commit ea8d5241
Author: Michael Davis <michael.davis@cern.ch>
Date:   Thu Aug 3 10:54:49 2017 +0200

    [XrdSsi] Updates eos_messages.proto and deletes Opaque Query

    Update the protobuf file to the version required by EOS-CTA SSI
    interface and delete all source code that depends on the previous
    version (i.e. all the opaque query code).

This removal should have been a replacement as opposed
to a hard delete.  The XrdCtaFilesystem::FSctl() method
should have been re-implemented as follows:

int XrdCtaFilesystem::FSctl(const int cmd, XrdSfsFSctl &args, XrdOucErrInfo &eI
  (void)cmd; (void)args; (void)eInfo; (void)client;
  eInfo.setErrInfo(ENOTSUP, "Not supported.");
  return SFS_ERROR;
}

Problem can occur in case of lock expiration. The request is still updated and should be handled as such.
The previous behaviour led to orphaned objects.

The problem is only seen while fetching the queues for scheduling. This commit detect the situation, logs and
skips the queue.
Also fixed typo in exception name.

Update the protobuf file to the version required by EOS-CTA SSI
interface and delete all source code that depends on the previous
version (i.e. all the opaque query code).