Don't update/rewrite dsts.ini when iniReadFile returns NULL

Even if the empty, iniReadFile() should return an empty list (not NULL),
NULL indicates a file read (or unlikely malloc failure) - so don't write back
what we read and return false (result) instead.

Part of likely work-around of issue #791: it's better to not increment stats
upon a file read error than to reset them all to zero.