SLING-7392 Pick up manifest generated by bnd Maven Plugin

enable profile when bnd file exists
diff --git a/pom.xml b/pom.xml
index 9e6c8b7..57a9287 100644
--- a/pom.xml
+++ b/pom.xml
@@ -508,7 +508,7 @@
             <id>bundle</id>
             <activation>
                 <file>
-                    <exists>target/classes/META-INF/MANIFEST.MF</exists>
+                    <exists>bnd.bnd</exists>
                 </file>
             </activation>
             <build>