Improved error reporting for OS X reverser dns lookup

[huntc]

Less scary.

[huntc]

Sample output:

huntc$ sandbox run 2.1.0 --no-default-features
Error: 
	Unfortunately, because of a known Java 8 issue on macOS,
	hostname lookups on your machine will take more than 5 seconds.

	This will prevent ConductR from starting.

	Fortunately, there is an easy, quick fix. Just add 'ChristohersMBP2.lan' to your /etc/hosts file. e.g.:

		127.0.0.1   localhost ChristohersMBP2.lan
		::1         localhost ChristohersMBP2.lan

	Note that you will need to use sudo to edit the /etc/hosts file.
	Use your favorite editor to do this e.g. 'sudo vi /etc/hosts'

	To learn more about the Java 8 issue: http://stackoverflow.com/questions/39636792/jvm-takes-a-long-time-to-resolve-ip-address-for-localhost

huntc$ 

[fsat]

Code change itself lgtm - but I think we should continue asserting the output of the message.

[fsat]

I think we should continue asserting the message, especially since there is part of the message where the socket.gethostname is being inserted in the message.

[huntc]

I disagree - it is quite painful to maintain such tests...