WARNING: do not (re-) prepare dde_linux port!

Dear genodians,

a recent regression within the dde_linux port description may lead to data-loss!

When preparing the dde_linux port although it is already available, e.g., to overwrite local changes in the contrib sources, non-commited changes of any git repository above your contrib directory (normally this will be your genode repository) will get reset hard. This regression went into the codebase with the update of 'wpa_supplicant' within the last release. Have a look at:

https://github.com/genodelabs/genode/issues/2959

for further details. We will provide a fix for this issue soon. In the meantime it is safe to do a prepare_port for dde_linux when it is not prepared yet.

Sorry for the inconvenience & regards Stefan