do not add empty strings when checking for relative symlinks

[flaviogrossi]

hi,

i think i found a problem when the check for symlinks in initialize_shared_storage is done

if no symlinks are found, an empty string is returned resulting in a value like [""] for the variable relative_symlinks, which evaluates to true in the test immediately after, raising an exception in the print statement

this should fix the problem

thanks, flavio

[flaviogrossi]

any news?