(PE-31797) Upgrade jetty to 9.40

[Magisus]

Jetty 9.39 seems to be causing some issues in Puppet Server, so this
commit rolls us forward to the next version that was just released,
which might have a fix for connections getting reset.

[Magisus]

I'm eyeing this bug jetty/jetty.project#6152 as potentially related to our issues, which is supposedly fixed with jetty/jetty.project#6142. I'm not totally sure if it's related: I have been unable to reproduce this locally and check out server logs, and the agent swallows some errors with the connection, see https://tickets.puppetlabs.com/browse/PUP-3238.

The failed output is:

Last 10 lines of output were:
	Info: Retrieving pluginfacts
	Notice: /File[/opt/puppetlabs/puppet/cache/facts.d]/mode: mode changed '0750' to '0755'
	Info: Retrieving plugin
	Notice: /File[/opt/puppetlabs/puppet/cache/lib/foo.rb]/ensure: removed
	Info: Retrieving locales
	Error: Could not retrieve catalog from remote server: Request to https://sneaky-cooling.delivery.puppetlabs.net:8140/puppet/v3/catalog/rundown-miner.delivery.puppetlabs.net?environment=production interrupted after 0.003 seconds
	Wrapped exception:
	end of file reached
	Warning: Not using cache on failed catalog
	Error: Could not retrieve catalog; skipping run

[steveax]

👍

[Magisus]

This update appears to have fixed our test issue.