Use pivotal-golang for localip [#82988760]

Signed-off-by: Kris Hicks <krishicks@gmail.com>
bump loggregatorlib

4f97b67 Ginko-ify signature package tests

automatic promotion by GoCD workflow Loggregatorlib/147 > UnitTests/1 > UnitTests
Merge branch 'Amit-PivotalLabs-pivotal-golang-localip' into develop

Closes https://github.com/cloudfoundry/loggregator/pull/34