Merge tag 'sparks-3.5.1' into develop

3.5.1
workaround the LANG problem as well as I can, but it's still ugly. Thanks, `LANG=C` nor `unset LANG` not working…
Avoid less-useful-now warnings.
Isolate 2 @tasks into a try/except block, for the only moment where Fabric is not yet installed and setup.py runs the `__init__.py` file, which fails. But unseen before because on all machine I update sparks on, fabric is already installed. Spotted on worker-04, on which I install from scratch.
bump version in __init__.py
Merge branch 'release/3.5.2'