Only write what was read

Without a length parameter here, we write the entire buffer,
including any bogus values that come after whatever we read. This
is the cause of null bytes getting into generated poms for gems.

Author: headius

ruby-tools/src/main/java/de/saumya/mojo/ruby/script/AntLauncher.java

@@ -147,8 +147,9 @@ private void writeInto(File file, OutputStream outputStream) throws IOException
         byte[] buffer = new byte[1024 * 4];
         final InputStream fileIS = new FileInputStream(file);
 
-        while (fileIS.read(buffer) > 0) {
-            outputStream.write(buffer);
+        int read = 0;
+        while ((read = fileIS.read(buffer)) > 0) {
+            outputStream.write(buffer, 0, read);
         }
     }