Puppet37

Edits to address 3.7 doc tickets: 
DOCS-1137
DOCS-1130
DOCS-1148
We should give a more user-friendly explanation here. The main points are:

- The default value (false) is good for agent nodes. Since the software installed on an agent can change during a Puppet run, leaving the setting at `false` can make plugins work more reliably, by persistently checking whether the plugin is suitable instead of remembering the old answer.
- Since the software installed on a puppet master server **doesn't** change while it's serving an agent, checking over and over again is pointless; the answer isn't going to change. And since checking takes precious time, you can get better performance by changing this setting to `true`. 

Want to take a crack at reducing that to one sentence?