Merge branch 'pr/3146' into stable
- pr/3146: (maint) Modify other uses of get() to get!() (PUP-3244) Add Puppet::Environment::Directories#get! method (PUP-3244) Validate Environment Before Setting (PUP-3244) Acceptance Tests for Nonexistent Environments (PUP-3244) ENC ignores missing directory environments
Closes GH-3146