Hook newrelic.properties for auto switch between debug and release builds.

HockNewRelicProperties.groovy

android.applicationVariants.all { variant ->
    task ("prepareNewRelicProperties${variant.name.capitalize()}"){
        doLast {
            copy {
                from variant.buildType.debuggable ? "${project.projectDir}/src/debug/newrelic.properties" : "${project.projectDir}/src/release/newrelic.properties"
                into "${project.projectDir}"
            }
        }
    }
    tasks.getByName("prepare${variant.name.capitalize()}Dependencies").dependsOn("prepareNewRelicProperties${variant.name.capitalize()}")
}