because updating documents in _users may change the credentials
for the arangorestore user itself, which may lead to all follow-up
requests by arangorestore being rejected with "authorized"/"forbidden"
* port of feature-3.4/mv-gzip-export to devel branch
* add explicit namespaces so gcc 6.3.0 would successfully compile
* add conditional cleanup of ENCRYPTION file from another branch
* use _lseek() for Windows build to avoid deprecated warning.
* change from ifdef for lseek variants to TRI_LSEEK.
* force Windows lseek to return Linux expected type.
* make arangorestore not report errors about the target database not found
when it is invoked with option `--create-database true`. In this case,
arangorestore should not print an error but simply create the target
database. This patch implements this change.
Additionally, it aborts the startup of arangorestore in case there are
any errors. Previously, the startup phase went on even when no connection
could be established, which led to useless follow-up errors being printed.
* simplify error handling a bit