This update for varnish fixes the following issues:

Security issue fixed:

- CVE-2019-15892: Fixed a potential denial of service by sending crafted HTTP/1 requests (boo#1149382).

Non-security issues fixed:

- Updated the package to release 6.2.1.
- Added a thread pool watchdog which will restart the worker process if scheduling tasks onto worker threads appears stuck. The new parameter "thread_pool_watchdog" configures it.
- Disabled error for clobbering, which caused bogus error in varnishtest.