am 45e56fd5: cherypick from mr2: Ib7e08e719b6b9c9b1e8116e6e2a77611f046b276 Switch APK signing from MD5WithRSA to SHA1WithRSA.

* commit '45e56fd5e1d3747cc1a9f1ecd5883ee491bff532':
  cherypick from mr2: Ib7e08e719b6b9c9b1e8116e6e2a77611f046b276 Switch APK signing from MD5WithRSA to SHA1WithRSA.