348366 Only remember cancel if dialog explicitly signals cancel

- Back-port of c56d308. Differences: The bundle versions are adapted
  according to the rules for the maintenance branch R37x.
- Introduced a new constant in UIServices to give the implementations
  the possibility to explicitly indicate that the user cancelled a
  prompt for password.
- Only remember cancel in class Credentials on explicit user cancels.
  This ensures that the authentication prompt is shown at least once.

Bug: 348366 - [repository] Cannot update from update site with authentication
7 files changed
tree: 2b671f682ec11b6959a270a425bb0f6c364d50b9
  1. bundles/
  2. examples/
  3. features/
  4. org.eclipse.equinox.p2.releng/