Bug 537833 - Default Linux Secure settings can cause error

- Linux password provider mechanism does not currently work on certain
  Linux setups
- add new canUnlock() jni method to the o.e.e.security.linux.x86_64
  native c code
- add new IValidatingPasswordProvider interface so a validation
  step can be requested by a password provider
- have LinuxPasswordProvider implement IValidatingPasswordProvider
  and add new isValid() method which calls canUnlock() and
  returns true or false accordingly
- change org.eclipse.equinox.security MANIFEST.MF to allow
  Linux password provider to use IValidatingPasswordProvider interface
- in PasswordProviderSelector.findAvailableModules() validate any
  provider that implements IValidatingPasswordProvider
- replace libkeystorelinuxnative.so

Change-Id: I9812390b863f5dcb0df452a371e40945c0de2bf8
Signed-off-by: Jeff Johnston <jjohnstn@redhat.com>
9 files changed