Revert "update to Eclipse 2020-03 RCP base"

This reverts commit 077a6f8011.

com.minres.scviewer.database.leveldb/META-INF/MANIFEST.MF

@@ -9,6 +9,7 @@ Import-Package: org.osgi.framework;version="1.3.0"
 Automatic-Module-Name: com.minres.scviewer.database.leveldb
 Service-Component: OSGI-INF/*.xml
 Require-Bundle: com.minres.scviewer.database;bundle-version="1.0.0",
+ org.eclipse.equinox.util;bundle-version="1.0.500",
  org.eclipse.equinox.ds;bundle-version="1.4.200",
  org.eclipse.osgi.services;bundle-version="3.4.0"
 Bundle-ActivationPolicy: lazy