CVE-2022-3650: ceph-crash: fix stderr handling

CVE-2022-3650: ceph-crash: fix stderr handling

Bug: a77b47eeeb5770eeefcf4619ab2105ee7a6a003e
Signed-off-by: Tim Serong <tserong@suse.com>
Bug-Debian: https://bugs.debian.org/1024932
Origin: upstream, https://github.com/ceph/ceph/commit/45915540559126a652f8d9d105723584cfc63439
Last-Update: 2022-11-28

Popen.communicate() returns a tuple (stdout, stderr), and stderr
will be of type bytes, hence the need to decode it before checking
if it's an empty string or not.

Gbp-Pq: Name CVE-2022-3650_2_ceph-crash_fix_stderr_handling.patch