[Libreoffice] [REVIEW] Fix reading .doc comments (fdo#45255)

[Lubos Lunak]

 The regression is caused by commit 8434a6966914547451489db6828b31ae86901186, 
which added size checks, but incorrectly - remainingSize() is called before 
the seek to the right position is done, which occassionally makes the code 
believe the file is corrupt.

 I don't actually know the format enough to be certain about the fix, but I 
expect it is quite clear from the logic of the thing, so I've committed as 
b5a73d4b2b283d3d1a57ac0f66b608998960a873 . Please review and backport.

-- 
 Lubos Lunak
 l.lunak at suse.cz