Remove needless parent from main pom.xml

The pom.xml files in the individual projects contain a reference to the
incubator parent module.

Since the main pom.xml file in the repo root only groups these modules,
it doesn't require this reference itself.

Change-Id: I99d1f2a4e3799b730f74afdfd6100998bc493c8c

pom.xml

diff --git a/pom.xml b/pom.xml
index 07bdd3f..ba37485 100644
--- a/pom.xml
+++ b/pom.xml
@@ -14,14 +14,9 @@
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
-  <parent>
-    <groupId>org.eclipse.rap.incubator</groupId>
-    <artifactId>org.eclipse.rap.incubator-parent</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
-    <relativePath>../org.eclipse.rap.incubator.releng/releng/org.eclipse.rap.incubator.releng/parent</relativePath>
-  </parent>
-
+  <groupId>org.eclipse.rap.incubator</groupId>
   <artifactId>org.eclipse.rap.addons.chart.build</artifactId>
+  <version>0.1.0-SNAPSHOT</version>
   <packaging>pom</packaging>
 
   <modules>