Bug 574622: Persist remembered accepted licenses in SimpleLicenseManager

Additionally simplify assembling of list of accepted license digests,
replace StringTokenizer by a corresponding split Pattern and make the
fields private final.

Change-Id: Icd7d6c28dd9e89ac93cd40c20c67602fbf59e8d7
Signed-off-by: Hannes Wellmann <wellmann.hannes1@gmx.net>
Reviewed-on: https://git.eclipse.org/r/c/equinox/rt.equinox.p2/+/182707
Tested-by: Equinox Bot <equinox-bot@eclipse.org>
Reviewed-by: Lars Vogel <Lars.Vogel@vogella.com>
3 files changed