build: Move flatten config out of execution

This caused issues with install/deploy the unflattened pom. So
the bom for 1.2.0 is unusable.

Signed-off-by: BJ Hargrave <hargrave@us.ibm.com>

examples/osgi-test-example-mvn/pom.xml

@@ -269,16 +269,16 @@
 					<groupId>org.codehaus.mojo</groupId>
 					<artifactId>flatten-maven-plugin</artifactId>
 					<version>1.2.7</version>
+					<configuration>
+						<flattenMode>oss</flattenMode>
+					</configuration>
 					<executions>
 						<execution>
 							<id>flatten</id>
 							<phase>process-resources</phase>
 							<goals>
 								<goal>flatten</goal>
 							</goals>
-							<configuration>
-								<flattenMode>oss</flattenMode>
-							</configuration>
 						</execution>
 						<execution>
 							<id>flatten-clean</id>

pom.xml

@@ -343,16 +343,16 @@ SPDX-License-Identifier: ${project.licenses[0].name}
 					<groupId>org.codehaus.mojo</groupId>
 					<artifactId>flatten-maven-plugin</artifactId>
 					<version>1.2.7</version>
+					<configuration>
+						<flattenMode>oss</flattenMode>
+					</configuration>
 					<executions>
 						<execution>
 							<id>flatten</id>
 							<phase>process-resources</phase>
 							<goals>
 								<goal>flatten</goal>
 							</goals>
-							<configuration>
-								<flattenMode>oss</flattenMode>
-							</configuration>
 						</execution>
 						<execution>
 							<id>flatten-clean</id>