ext4/006: take into account updates to _scratch_fuzz_modify()

ext4/006: take into account updates to _scratch_fuzz_modify()

Test ext4/006 takes into account the number of lines produced by its own
output.  However, changes introduced to function _scratch_fuzz_modify() by
commit 9bab148bb3c7 ("common/fuzzy: exercise the filesystem a little harder
after repairing"), modified the output.  Namely, the following three lines
were removed:

	echo "+++ touch ${nr} files"
	echo "+++ create files"
	echo "+++ remove files"

And a new one was added:

	echo "+++ stressing filesystem"

However, the usage of 'fsstress' also added an extra line with:

	printf("seed = %ld\n", seed);

So the delta is one line (-3 + 2).

Modify test ext4/006 to take this change into account.

Signed-off-by: "Luis Henriques (SUSE)" <luis.henriques@linux.dev>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>