Adding cta_tagged_rpm stage. CTA_RELEASE and CTA_VERSION are not exported as is to avoid overriding environment variables used by cmake. Therefore I am using TAG_VERSION and TAG_RELEASE.

Fixing issue #108: rpmbuild runs cmake underneath, but this second instance needs to propagate the variables passed to the initial cmake.

Fixed.  The cta command-line tool will now timeout after
15 seconds when trying to connect to the CTA front-end
daemons.  The previous timeout was 8 minutes.

The test remains disabled as it still take quite a bit of time.

This is done by replacing unique_ptr/bare pointer with 2 shared_ptr.
Also added suppressions for helgrind complains about rados.

Print CTA_BUILD_ID in the jobs and not the full SHA of the commit of course. The generated rpm version was OK but the logs were useless.

`CI_BUILD_REF` environment variable has been dropped in [gitlab 9.0](https://cern.service-now.com/service-portal/view-outage.do?n=OTG0037271)

Fixed.

Removed the dependency between cta-cli and the xrootd
"meta package".

Lambdas were stored on stack and passed to async. They are now stored in object with proper lifetime.
Improved ArchiveMount::getNextJobBatch(): we now clean up the empty queues.

BackendVFS now throws the same exceptions as BackendRados.
The exceptions of the user provided update callback are now passed through.
A unit test was added.

This reverts commit 22685812.

Added comment to cta_catalogue_db.conf.example that explains which connection string should be used when

Added an intermediate interface to reuse SchedulerDatabaseFactory.
Added optional debug infos for BackendVFS constructor.
The unit test is currently disabled.

The ArchiveJobs are now updated using asynchronous IO.

When dropping the database schema, tables and sequences are only
dropped if they are present.

This commit avoids the message "table or view does not exist" by
modifying cta-catalogue-schema-drop to simply not try to delete
tables that do not exist.

cta/CTA#87 cta-catalogue-delete-all-data and cta-catalogue-schema-drop should require interactive confirmation

Removed the now redundant locking commands for the catalogue schema.
These commands were made redundant when the cta-catalogue-schema-drop
command was made interactive.

The VFS implementation only launches the operation in the background (via std::async).
The Rados implementation uses the aio features of Rados. Lock and update are launched in the background via std::async.
Also now uses override for Backend virtual function.

cta/CTA#87 cta-catalogue-delete-all-data and cta-catalogue-schema-drop should require interactive confirmation

Made the cta-catalogue-schema-drop command interactive