add README.md to rat excludes
diff --git a/brooklyn-dist/vagrant/pom.xml b/brooklyn-dist/vagrant/pom.xml
index 3fc1844..fbe6539 100644
--- a/brooklyn-dist/vagrant/pom.xml
+++ b/brooklyn-dist/vagrant/pom.xml
@@ -66,5 +66,18 @@
                 </executions>
             </plugin>
         </plugins>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.rat</groupId>
+                    <artifactId>apache-rat-plugin</artifactId>
+                    <configuration>
+                        <excludes combine.children="append">
+                            <exclude>src/main/vagrant/README.md</exclude>
+                        </excludes>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
     </build>
 </project>