Adjust bwc version

Relates #39687

Author: dnhatn

server/src/main/java/org/elasticsearch/action/admin/indices/close/CloseIndexResponse.java

@@ -60,7 +60,7 @@ public void readFrom(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(Version.V_7_2_0)) {
             readShardsAcknowledged(in);
         }
-        if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (in.getVersion().onOrAfter(Version.V_7_3_0)) {
             indices = unmodifiableList(in.readList(IndexResult::new));
         } else {
             indices = unmodifiableList(emptyList());
@@ -73,7 +73,7 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(Version.V_7_2_0)) {
             writeShardsAcknowledged(out);
         }
-        if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_7_3_0)) {
             out.writeList(indices);
         }
     }

server/src/test/java/org/elasticsearch/action/admin/indices/close/CloseIndexResponseTests.java

@@ -100,7 +100,7 @@ public void testBwcSerialization() throws Exception {
                 }
                 assertThat(deserializedResponse.isAcknowledged(), equalTo(response.isAcknowledged()));
                 assertThat(deserializedResponse.isShardsAcknowledged(), equalTo(response.isShardsAcknowledged()));
-                if (version.onOrAfter(Version.V_8_0_0)) {
+                if (version.onOrAfter(Version.V_7_3_0)) {
                     assertThat(deserializedResponse.getIndices(), hasSize(response.getIndices().size()));
                 } else {
                     assertThat(deserializedResponse.getIndices(), empty());