Update SOURCE_IMAGE and SOURCE_PKG in release-publish.
Update SOURCE_IMAGE and SOURCE_PKG in release-publish.

Change-Id: I2b9a5d62438feb590cf46642647339057e3eab7a

cloudendpoints/esp,cloudendpoints/esp,cloudendpoints/esp,cloudendpoints/esp,cloudendpoints/esp,cloudendpoints/esp,cloudendpoints/esp,cloudendpoints/esp