Collection of fixes

[aplanas]

• Close the files before returning, not when there is a fail (and the file handler will be NULL)
• Find EFI token in a different order, and check that the directory exist to mark the end of the search
• Correct the length calculation for the UTF16 string

[aplanas]

cc @okirch

[aplanas]

@okirch I also updated the version to 0.5.0, so we can have a new release in OBS