Fix variable expansion problem when SOTA_PACKED_CREDENTIALS is not set.
Reported by Stevan, traced to the problem by me, actually fixed by
Anton.
-SRC_URI_append = "${@'file://${SOTA_PACKED_CREDENTIALS}' if d.getVar('SOTA_PACKED_CREDENTIALS', True) else ' '}"
+SRC_URI_append = "${@('file://' + d.getVar('SOTA_PACKED_CREDENTIALS', True)) if d.getVar('SOTA_PACKED_CREDENTIALS', True) else ''}"
