Update the jdk version

This is needed for the gradle based build system (see servo/servo#15773 (comment))
servo · bors-servo · Mar 13, 2017 · Mar 13, 2017 · Mar 13, 2017 · 0150d2942dde10acd814e4bdd32827f61d9fc15f
commit 0150d2942dde10acd814e4bdd32827f61d9fc15f
diff --git a/servo-build-dependencies/android.sls b/servo-build-dependencies/android.sls
@@ -23,7 +23,7 @@ android-dependencies:
       - libc6:i386
       - libstdc++6:i386
       {% endif %}
-      - default-jdk
+      - openjdk-8-jdk
       - ant
       - expect
       - gcc