rename shield audit indices to keep naming consistent

This change renames the shield audit indices to keep naming consistent with other plugins.
The name of the index uses '_' to separate words, a '-' to separate the prefix from the time
portion, and '.'s to separate the different portions of the date.

Closes elastic/elasticsearch#925

Original commit: elastic/x-pack-elasticsearch@8ca6856e4a

src/main/java/org/elasticsearch/shield/audit/index/IndexAuditTrail.java

@@ -73,7 +73,7 @@ public class IndexAuditTrail extends AbstractComponent implements AuditTrail {
     public static final TimeValue DEFAULT_FLUSH_INTERVAL = TimeValue.timeValueSeconds(1);
     public static final IndexNameResolver.Rollover DEFAULT_ROLLOVER = IndexNameResolver.Rollover.DAILY;
     public static final String NAME = "index";
-    public static final String INDEX_NAME_PREFIX = ".shield-audit-log";
+    public static final String INDEX_NAME_PREFIX = ".shield_audit_log";
     public static final String DOC_TYPE = "event";
     public static final String ROLLOVER_SETTING = "shield.audit.index.rollover";
 

src/main/java/org/elasticsearch/shield/audit/index/IndexNameResolver.java

@@ -12,10 +12,10 @@ import org.joda.time.format.DateTimeFormatter;
 public class IndexNameResolver {
 
     public enum Rollover {
-        HOURLY  ("-yyyy-MM-dd-HH"),
-        DAILY   ("-yyyy-MM-dd"),
-        WEEKLY  ("-yyyy-w"),
-        MONTHLY ("-yyyy-MM");
+        HOURLY  ("-yyyy.MM.dd.HH"),
+        DAILY   ("-yyyy.MM.dd"),
+        WEEKLY  ("-yyyy.w"),
+        MONTHLY ("-yyyy.MM");
 
         private final DateTimeFormatter formatter;
 

src/main/resources/shield_audit_log.json

@@ -1,5 +1,5 @@
 {
-  "template": ".shield-audit-log*",
+  "template": ".shield_audit_log*",
   "order": 2147483647,
   "settings": {
     "index.mapper.dynamic" : false