CVE-2022-2850 - Sync_repl may crash while managing invalid cookie (#5420) - Issue...

CVE-2022-2850 - Sync_repl may crash while managing invalid cookie (#5420) - Issue 5418

Bug description:
	If the servers receives an invalid cookie without separator '#',
	it parses it into an empty cookie (Sync_Cookie) instead of a NULL
	cookie (failure).
	Later it sigsegv when using the empty cookie.

Fix description:
	If the parsing fails return NULL

relates: #5418

Reviewed by: Viktor Ashirov, Mark Reynolds, William Brown, Simon
 Pichugin (thanks !)

Origin: backport, commit:513a763b551848e5532ec22bb0086464aa09252f

Gbp-Pq: Name CVE-2022-2850-Sync_repl-may-crash-with-invalid-cookie.patch