Adjust serialization version for can contain data

This commit adjusts the serialization version for the can contain data
field on roles, as this logic has now been backported to 7.10 and 7.x.

server/src/main/java/org/elasticsearch/cluster/node/DiscoveryNode.java

@@ -261,7 +261,7 @@ public class DiscoveryNode implements Writeable, ToXContentFragment {
             final String roleName = in.readString();
             final String roleNameAbbreviation = in.readString();
             final boolean canContainData;
-            if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (in.getVersion().onOrAfter(Version.V_7_10_0)) {
                 canContainData = in.readBoolean();
             } else {
                 canContainData = roleName.equals(DiscoveryNodeRole.DATA_ROLE.roleName());
@@ -294,7 +294,7 @@ public class DiscoveryNode implements Writeable, ToXContentFragment {
             final DiscoveryNodeRole compatibleRole = role.getCompatibilityRole(out.getVersion());
             out.writeString(compatibleRole.roleName());
             out.writeString(compatibleRole.roleNameAbbreviation());
-            if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (out.getVersion().onOrAfter(Version.V_7_10_0)) {
                 out.writeBoolean(compatibleRole.canContainData());
             }
         }