Use our build server as source for android images

packaging/snap/snapcraft.yaml

@@ -22,7 +22,7 @@ parts:
     install: |
       # FIXME: downloading with a source: field doesn't work as snapcraft
       # expects the downloaded file to be an archive it can extract.
-      wget https://s3.eu-central-1.amazonaws.com/anbox/images/anbox-android-1.img
+      wget http://build.anbox.io/android-images/2017/04/12/android_1_amd64.img
       mv anbox-android-1.img $SNAPCRAFT_PART_INSTALL/android.img
   anbox-common:
     plugin: dump