Fix razor-server service on EL7

[smcclellan]

Systemd's .service file was referencing the absent HTTP_PORT variable. This
resulted in an empty string being passed to the service for its http.port
argument. Since an empty string can't be translated to an integer, this error
resulted:

JBAS014688: Wrong type for port. Expected [EXPRESSION, INT] but was STRING

The fix is simply supplying this environment variable, which works here in
the .env file.

Fixes https://tickets.puppetlabs.com/browse/RAZOR-629

[samwoods1]

Any reason we might want to check to see if HTTP_PORT is already set before arbitrarily setting it to 8080? I can't think why it would be anything other than that, but who knows.

[smcclellan]

We may potentially want to use a more descriptive name for the variable, like $RAZOR_HTTP_PORT or something. For now, this matches the behavior on the PE side, so I will ticket this to fix in both places for a future PR.

Update: Tracked by this PR.

[aperiodic]

It's a small cost to add a newline add the end of files and it's generally recommended to avoid weird issues with some tools.

[smcclellan]

Fixed.

[pcarlisle]

there's an intellij setting to always do this

[aperiodic]

The "preferIPv4Stack" option sounds like it'll still let you use IPv6, but in fact it disables IPv6 entirely. Is this what you want? Will folks never want to use razor on IPv6-only hosts?

[smcclellan]

This is probably worth keeping in mind. I haven't heard any users bringing up any issues with this (it's been that way since the start). If this comes up as an issue, we can create a ticket and do testing without this argument.

[smcclellan]

Added NEWS.md entry, rebased, and merged.