Now we are also tolerant of whether paths in config file do or do
not have a trailing slash.

Pathnames from the DB must have a leading slash if we have to strip off
the CASTOR prefix, but in any case we will convert all filenames to
absolute filenames by adding the EOS prefix.

This test is failing, probably because EOS version in CI was compiled
against an incompatible version of the grpc protobuf. Will obtain a new
EOS version and retry.

gRPC user needs to be in EOS +sudo group

castor-dbtools is required by cta-migration-tools

Added activable logs to the RetrieveQueueStatistics cache for debugging

An example value of sys.retrieve.error is as follows:

[itctabuild02] ~ > sudo eos attr ls /eos/dev/userfiles/testdir_1/test_1 | grep sys.retrieve.error
sys.retrieve.error="Garbage collected at 2019/09/09 16:27:26.609570"
[itctabuild02] ~ >

This can now be done without tearing down and re-creating the containers.

Added error messages in case of problems for easier diagnosis.

Conflicts:
	continuousintegration/docker/ctafrontend/cc7/opt/run/bin/ctaeos-mgm.sh