As EOS is parsing stderr to get the archive ID

Recovery blob is deprecated. EOS will fill in metadata fields in the
protocol buffer and we need to decide what will be stored in the
database.

So we can see how bash shell strings are being escaped and what actually
appears in the protocol buffer.

Sets retrieve workflow in eos_wfe_scripts back to the old cta command
for now. Try to get simple test to work first.

This will be validated in the ssi branch and merged into master later.

The code in this part was uselessly taking exclusive root locks, leading to locking
fights when starting all drive as the same time in bigger systems.

This happens when the notification is received multiple times. This did not show
before full scale test.

The locking is now handled in a single function.
This functions is also used in the asynchronous operations. This operations have
been simplified in this operation: we now do a synchronous stat after the locking.
Previously stat was the first asynchronous operation. This will slightly slow down
the async operations (for the gain of code simplicity).

This commit only replaces backoff with notifications in exclusive locks, for validation
with a multithreaded unit test. This proof of concept is considered as working, as the
measured gap between a lock release and a lock take never exceeds ~1/4 of a second, with a typical
release-lock gap in the few ms to few tens of ms.

Done.

Replaced set_target_properties( .. .. INSTALL_RPATH ..) with set_property (TARGET .. APPEND PROPERTY INSTALL_RPATH ..)