Remove unused constructor

Author: gmarouli

server/src/main/java/org/elasticsearch/action/downsample/DownsampleConfig.java

@@ -101,17 +101,6 @@ public class DownsampleConfig implements NamedWriteable, ToXContentObject {
         );
     }
 
-    /**
-     * Create a new {@link DownsampleConfig} using the given configuration parameters.
-     * @param fixedInterval the fixed interval to use for computing the date histogram for the rolled up documents (required).
-     * @deprecated please use {@link DownsampleConfig#DownsampleConfig(DateHistogramInterval, SamplingMethod)}, this method is being kept
-     * until the sampling method is completely integrated with ILM and DLM.
-     */
-    @Deprecated
-    public DownsampleConfig(final DateHistogramInterval fixedInterval) {
-        this(fixedInterval, null);
-    }
-
     /**
      * Create a new {@link DownsampleConfig} using the given configuration parameters.
      * @param fixedInterval the fixed interval to use for computing the date histogram for the rolled up documents (required).