serverspec be able to override user for tests

[sarcasticadmin]

Description

Currently we hard code the user:

scale-network/tests/serverspec/spec/spec_helper.rb

Lines 25 to 37 in dea2047

	if ENV['TEST_TYPE'].start_with?('openwrt')
	options[:user] = 'root'
	# Disable sudo
	set :disable_sudo, true
	# Force os detection due to errors on openwrt
	set :os, :family => 'linux'
	else
	#options[:user] ||= Etc.getlogin
	# TODO: Need to not hard code this
	# But ok to assume this user for now
	options[:user] = 'ubuntu'
	end

Acceptance Criteria

• user is overridable for serverspec