Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Error Prone: Fix DefaultCharset in ListProjectsIT
  Bazel: Enable Error-Prone by default
  Parallelize account migration in schema 146 migration
  Fix _nextStepHandle not being assigned a value when scrolling
  Elasticsearch: Remove redundant handling of 'ignore_unmapped' property
  Elasticsearch: Fix support for V6 versions earlier than 6.7.*
  Clarify introduction to external IDs
  ExternalIdNotes: Improve grammar in checkState messages
  Update git submodules
  Add example of external ID key in external ID documentation
  Minor grammatical fixes in external ID documentation
  ElasticVersionTest: Add missing assertions on V6_7

Also update the replication plugin revision to include the fix:

  HttpResponse: Specify charset in constructor of InputStreamReader

which is needed due to enabling error prone checks on core plugins.

Change-Id: I90394f5c0d6aaf88b1169c26ceb65b699fddfe77

java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java

@@ -805,7 +805,7 @@ public class ExternalIdNotes extends VersionedMetaData {
       }
       checkState(
           accountId.equals(extId.accountId()),
-          "external id %s belongs to account %s, expected account %s",
+          "external id %s belongs to account %s, but expected account %s",
           extId.key().get(),
           extId.accountId().get(),
           accountId.get());
@@ -863,7 +863,7 @@ public class ExternalIdNotes extends VersionedMetaData {
     ExternalId actualExtId = ExternalId.parse(noteId.name(), raw, noteDataId);
     checkState(
         extId.equals(actualExtId),
-        "external id %s should be removed, but it's not matching the actual external id %s",
+        "external id %s should be removed, but it doesn't match the actual external id %s",
         extId.toString(),
         actualExtId.toString());
     noteMap.remove(noteId);