ima: fix error handling logic when file measurement failed

ima: fix error handling logic when file measurement failed

commit 48c913b0272686d8139f262621e9e6460f6ca989 upstream.

Restore the error handling logic so that when file measurement fails,
the respective iint entry is not left with the digest data being
populated with zeroes.

Fixes: 035e6f439c50 ("ima: permit fsverity's file digests in the IMA measurement list")
Cc: stable@vger.kernel.org	# 5.19
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>