Changes packing from feature to pom

This ensures that the GPG signatures for the feature files are
uploaded to the Nexus repository when creating a release
diff --git a/karaf/features/pom.xml b/karaf/features/pom.xml
index 501a270..6d5bc0d 100644
--- a/karaf/features/pom.xml
+++ b/karaf/features/pom.xml
@@ -30,29 +30,59 @@
     <artifactId>brooklyn-library-features</artifactId>
     <name>Brooklyn Library Karaf Features</name>
     <description>Defines Karaf features for Karaf runtime</description>
-    <packaging>feature</packaging>
+    <packaging>pom</packaging>
 
     <build>
-        <pluginManagement>
-            <plugins>
-                <plugin>
-                    <groupId>org.apache.karaf.tooling</groupId>
-                    <artifactId>karaf-maven-plugin</artifactId>
-                    <version>${karaf.plugin.version}</version>
-                    <extensions>true</extensions>
-                </plugin>
-            </plugins>
-        </pluginManagement>
+        <resources>
+            <resource>
+                <directory>src/main/feature</directory>
+                <filtering>true</filtering>
+                <includes>
+                    <include>**/*</include>
+                </includes>
+            </resource>
+        </resources>
         <plugins>
             <plugin>
-                <groupId>org.apache.karaf.tooling</groupId>
-                <artifactId>karaf-maven-plugin</artifactId>
-
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-resources-plugin</artifactId>
+                <version>2.6</version>
                 <configuration>
-                    <startLevel>50</startLevel>
-                    <aggregateFeatures>true</aggregateFeatures>
-                    <resolver>(obr)</resolver>
+                    <useDefaultDelimiters>false</useDefaultDelimiters>
+                    <delimiters>
+                        <delimiter>${*}</delimiter>
+                    </delimiters>
                 </configuration>
+                <executions>
+                    <execution>
+                        <id>filter</id>
+                        <phase>generate-resources</phase>
+                        <goals>
+                            <goal>resources</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>build-helper-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>attach-artifact</goal>
+                        </goals>
+                        <configuration>
+                            <artifacts>
+                                <artifact>
+                                    <file>target/classes/feature.xml</file>
+                                    <classifier>features</classifier>
+                                    <type>xml</type>
+                                </artifact>
+                            </artifacts>
+                        </configuration>
+                    </execution>
+                </executions>
             </plugin>
         </plugins>
     </build>