fuzz: report error if Python code raised exception
I think that's what we wanted to do, given the most of the code block is
surrounded by try-except. 'lazymanifest(mdata)' is moved to the try block
as it can fail.
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown