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.

Author: jasontedor

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

@@ -261,7 +261,7 @@ public DiscoveryNode(StreamInput in) throws IOException {
             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 void writeTo(StreamOutput out) throws IOException {
             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());
             }
         }