Fixes UpdateSettingsRequestStreamableTests mutate bug

The mutate function in UpdateSettingsRequestStreamableTests did not
guarantee that the masterNodeTimeout and timeout values are definitely
changed and occassionally the randomTimeValue() method would select the
sime time value as the original request which caused a failure.

server/src/test/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequestStreamableTests.java

@@ -24,6 +24,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.Settings.Builder;
 import org.elasticsearch.common.util.CollectionUtils;
 import org.elasticsearch.test.AbstractStreamableTestCase;
+import org.elasticsearch.test.ESTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -38,8 +39,9 @@ public class UpdateSettingsRequestStreamableTests extends AbstractStreamableTest
     protected UpdateSettingsRequest mutateInstance(UpdateSettingsRequest request) {
         UpdateSettingsRequest mutation = copyRequest(request);
         List<Runnable> mutators = new ArrayList<>();
-        mutators.add(() -> mutation.masterNodeTimeout(randomTimeValue()));
-        mutators.add(() -> mutation.timeout(randomTimeValue()));
+        mutators.add(() -> mutation
+                .masterNodeTimeout(randomValueOtherThan(request.masterNodeTimeout().getStringRep(), ESTestCase::randomTimeValue)));
+        mutators.add(() -> mutation.timeout(randomValueOtherThan(request.masterNodeTimeout().getStringRep(), ESTestCase::randomTimeValue)));
         mutators.add(() -> mutation.settings(mutateSettings(request.settings())));
         mutators.add(() -> mutation.indices(mutateIndices(request.indices())));
         mutators.add(() -> mutation.indicesOptions(randomValueOtherThan(request.indicesOptions(),
@@ -72,7 +74,7 @@ public class UpdateSettingsRequestStreamableTests extends AbstractStreamableTest
 
     private static UpdateSettingsRequest copyRequest(UpdateSettingsRequest request) {
         UpdateSettingsRequest result = new UpdateSettingsRequest(request.settings(), request.indices());
-        result.masterNodeTimeout(request.timeout());
+        result.masterNodeTimeout(request.masterNodeTimeout());
         result.timeout(request.timeout());
         result.indicesOptions(request.indicesOptions());
         result.setPreserveExisting(request.isPreserveExisting());