SeaDrive linux crash on startup if /home/user/SeaDrive/ is not an empty dir

[chadek]

On linux, SeaDrive version 2.0.16 crash on startup if /home/user/SeaDrive/ is not an empty dir. This can be reproduce simply by creating a directory into SeaDrive folder. I don't know which behavior is best but if SeaDrive is meant not to start if his mount directory is not empty, then we should at least have a proper log/popup from seadrive-gui (can't find how open issues on other repo that's why I'm opening it here and it might be routed somewhere else).