BwC fix 2

Author: Andrey Ershov

server/src/main/java/org/elasticsearch/snapshots/SnapshotInfo.java

@@ -283,7 +283,11 @@ private SnapshotInfo(SnapshotId snapshotId, String repository, List<String> indi
     public SnapshotInfo(final StreamInput in) throws IOException {
         snapshotId = new SnapshotId(in);
         if (in.getVersion().onOrAfter(GetSnapshotsRequest.MULTIPLE_REPOSITORIES_SUPPORT_ADDED)) {
-            repository = in.readString();
+            if (in.readBoolean()) {
+                repository = in.readString();
+            } else {
+                repository = null;
+            }
         } else {
             repository = null;
         }
@@ -694,7 +698,12 @@ public static SnapshotInfo fromXContentInternal(final XContentParser parser) thr
     public void writeTo(final StreamOutput out) throws IOException {
         snapshotId.writeTo(out);
         if (out.getVersion().onOrAfter(GetSnapshotsRequest.MULTIPLE_REPOSITORIES_SUPPORT_ADDED)) {
-            out.writeString(repository);
+            if (repository != null) {
+                out.writeBoolean(true);
+                out.writeString(repository);
+            } else {
+                out.writeBoolean(false);
+            }
         }
         out.writeVInt(indices.size());
         for (String index : indices) {