am d421f57d: Fix mkyaffs2image extra flags in the release tools.

Merge commit 'd421f57d22009e4d9ce71298c2f93636ff9e7d9d' into gingerbread-plus-aosp

* commit 'd421f57d22009e4d9ce71298c2f93636ff9e7d9d':
  Fix mkyaffs2image extra flags in the release tools.