This reverts commit 0fd48fd7dab066db8a46e51775579c9ef507ca25.

We are facing some problem on rolling out the current 15.05-branch to
our devices because the image name changed.

The changed image name breaks compatibility for derived projects and
that's something which should only happen if there is a really good
reason (e.g. security fix).

Signed-off-by: Tim Niemeyer <tim@tn-x.org>

git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@49231 3c298f89-4303-0410-b956-a3cf2f4a3e73