killjava.sh Is Executable

Previously, changes to the packaging script to ensure that executable
permissions were propagated in all packaging circumstances missed that the
killjava.sh script needed to be executable as well.  This change updates the
packaging script to broaden the collection of files that get executable
permissions during packaging.

[resolves #408]

rakelib/stage_buildpack_task.rb

@@ -38,7 +38,7 @@ def copy_task(source, target)
       file(target => [source, parent]) do |t|
         cp t.source, t.name
 
-        if t.source.start_with? 'bin'
+        if t.source.include? 'bin'
           chmod 0o755, t.name
         else
           chmod 0o644, t.name