[releng] Use build parameter PLATFORM to choose the correct TP

Before, the neon TP was used by default.
Now, we use the PLATFORM paremeter to use the expected TP.

Change-Id: I02d909871a6167fe78ddd8c31da8f8b4f6dd273e
Signed-off-by: Damien Filliat <damien.filliat@thalesgroup.com>
diff --git a/releng/org.eclipse.amalgam.releng/pom.xml b/releng/org.eclipse.amalgam.releng/pom.xml
index 3a20957..b7ad1bb 100644
--- a/releng/org.eclipse.amalgam.releng/pom.xml
+++ b/releng/org.eclipse.amalgam.releng/pom.xml
@@ -1,11 +1,14 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-   Copyright (C) 2011, Obeo
+   Copyright (C) 2011, 2017, Obeo
 
    All rights reserved. This program and the accompanying materials
    are made available under the terms of the Eclipse Public License v1.0
    which accompanies this distribution, and is available at
    http://www.eclipse.org/legal/epl-v10.html
+
+   Contributors:
+     THALES GLOBAL SERVICES - Configuration modification
 -->
 
 <project xmlns="http://maven.apache.org/POM/4.0.0"
@@ -86,7 +89,7 @@
                             <groupId>org.eclipse.amalgam</groupId>
                             <artifactId>org.eclipse.amalgam.releng</artifactId>
                             <version>1.7.0-SNAPSHOT</version>
-                            <classifier>target_platforms/neon</classifier>
+                            <classifier>target_platforms/${PLATFORM}</classifier>
                         </artifact>
                     </target>
                     <environments>