Fix fatal RuntimeException reading public hostname and ip when running within vpc
* when priam.vpc=true SystemUtils.getDataFromUrl for the public hostname and ip throw a runtime exception prohibiting Priam from starting
* move setting the values down into the constructor and wrap SystemUtils.getDataFromUrl in try/catch
Updated filter checks since it cannot be null.

Introducing a default of "" for the filter QueryParam in BackupServlet.list had the side effect that any calls to /backup/list without specifying a filter would fail with "java.lang.IllegalArgumentException: No enum constant com.netflix.priam.backup.AbstractBackupPath.BackupFileType".
Merge pull request #328 from decbis/master

Updated filter checks since it cannot be null.
Merge pull request #315 from tjbaker/master

Fix fatal RuntimeException reading public hostname and ip when in vpc
Fix X-Y-Z node replacement.  X is a bad node that we need to bring up a new node to replace.
Y is a new node that is supposed to replace X but dies in the middle.  Z comes up to replace X but
think it should replace Y.  This fix helps Z to identify X, the original bad node.
Merge pull request #332 from timiblossom/master

Fix X-Y-Z node replacement.  X is a bad node that we need to bring up a ...
Merge branch 'master' into 1.2