[lille] remove unnecessary mounted key

data/grid5000/sites/lille/servers/carbonade.json

data/grid5000/sites/lille/servers/caulier.json

data/grid5000/sites/lille/servers/chimint-srv2.json

data/grid5000/sites/lille/servers/chiterne.json

data/grid5000/sites/lille/servers/fives.json

data/grid5000/sites/lille/servers/flandres.json

data/grid5000/sites/lille/servers/gardin.json

data/grid5000/sites/lille/servers/granche-srv1.json

data/grid5000/sites/lille/servers/granche-srv2.json

data/grid5000/sites/lille/servers/gwol-north.json

data/grid5000/sites/lille/servers/srv-data.json

data/grid5000/sites/lille/servers/welsh.json

input/grid5000/sites/lille/servers/physical.yaml