Expose generated sources to m2e

This fixes build errors shown when importing the operator into Eclipse
using the m2e plugin.

See https://stackoverflow.com/questions/7160006/m2e-and-having-maven-generated-source-folders-as-eclipse-source-folders

Change-Id: I88e816607ef1c2592d4d00f4ca52a6609d9b4e97

operator/pom.xml

diff --git a/operator/pom.xml b/operator/pom.xml
index 3697fbc..52c065a 100644
--- a/operator/pom.xml
+++ b/operator/pom.xml
@@ -366,6 +366,27 @@
 					<rerunFailingTestsCount>1</rerunFailingTestsCount>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>build-helper-maven-plugin</artifactId>
+				<version>3.4.0</version>
+				<executions>
+					<execution>
+						<id>add-source</id>
+						<phase>generate-sources</phase>
+						<goals>
+							<goal>add-source</goal>
+						</goals>
+						<configuration>
+							<sources>
+								<source>${project.build.directory}/generated-sources/annotations/</source>
+								<source>${project.build.directory}/generated-sources/java/</source>
+								<source>${project.build.directory}/generated-test-sources/java/</source>
+							</sources>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 </project>