Variable in dependency section can confuse org.apache.felix:maven-obr-plugin:install-file goal, so change to use explicit groupId

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@615724 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/org.osgi.service.obr/pom.xml b/org.osgi.service.obr/pom.xml
index 7f6910e..a875f2a 100644
--- a/org.osgi.service.obr/pom.xml
+++ b/org.osgi.service.obr/pom.xml
@@ -35,7 +35,7 @@
   <packaging>jar</packaging>
   <dependencies>
     <dependency>
-      <groupId>${pom.groupId}</groupId>
+      <groupId>org.apache.felix</groupId>
       <artifactId>org.osgi.core</artifactId>
       <version>1.0.0</version>
     </dependency>