Fix handling of target platform files with windows

Change-Id: Idf1813bfdfc33894740ecfe44c363f0f784a1308
Signed-off-by: Markus Duft <markus.duft@ssi-schaefer.com>
diff --git a/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/p2/TargetPlatformHelper.java b/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/p2/TargetPlatformHelper.java
index 615114e..44b9154 100644
--- a/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/p2/TargetPlatformHelper.java
+++ b/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/p2/TargetPlatformHelper.java
@@ -65,18 +65,20 @@
 		ITargetDefinition definition = null;
 		try {
 			URI tpDef = null;
-			if (tp.startsWith("/")) {
-				File f = new File(tp);
-				if (f.isFile()) {
-					tpDef = f.toURI();
-				}
-			} else if (bep != null) {
+			if (bep != null) {
 				IResource member = bep.findMember(tp);
 				if (member != null && member.exists() && member.getType() == IResource.FILE) {
 					tpDef = member.getLocationURI();
 				}
 			}
 
+			if (tpDef == null) {
+				File f = new File(tp);
+				if (f.isFile()) {
+					tpDef = f.toURI();
+				}
+			}
+
 			log.debug("looking up target platform, trying file: " + tpDef);
 
 			if (tpDef == null) {