git: openjdk/mobile: 8232209: Update double-conversion license file to version 3.1.5

[duke]

Changeset: 50ef4854
Author:    Hannes Wallnöfer <hannesw at openjdk.org>
Date:      2019-11-05 17:27:18 +0000
URL:       https://git.openjdk.java.net/mobile/commit/50ef4854

8232209: Update double-conversion license file to version 3.1.5

Reviewed-by: sundar

! src/jdk.scripting.nashorn/share/legal/double-conversion.md