FELIX-3349: align external manifest path with current project

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1490844 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/bundleplugin/src/main/java/org/apache/felix/bundleplugin/BundlePlugin.java b/bundleplugin/src/main/java/org/apache/felix/bundleplugin/BundlePlugin.java
index fa35abd..46be599 100644
--- a/bundleplugin/src/main/java/org/apache/felix/bundleplugin/BundlePlugin.java
+++ b/bundleplugin/src/main/java/org/apache/felix/bundleplugin/BundlePlugin.java
@@ -720,6 +720,10 @@
 
             // First grab the external manifest file (if specified and different to target location)
             File externalManifestFile = archiveConfig.getManifestFile();
+            if ( !externalManifestFile.isAbsolute() )
+            {
+                externalManifestFile = new File( currentProject.getBasedir(), externalManifestFile.getPath() );
+            }
             if ( null != externalManifestFile && externalManifestFile.exists()
                 && !externalManifestFile.equals( new File( manifestLocation, "MANIFEST.MF" ) ) )
             {