Upgrade instructions to use 16.04 slave and openjdk-8

Change-Id: I4ce3a4b3a89212b44e1bd4c9204f57f91a232304
diff --git a/.jenkins.d/10-get-sdk.sh b/.jenkins.d/10-get-sdk.sh
index d0810d9..87418ba 100755
--- a/.jenkins.d/10-get-sdk.sh
+++ b/.jenkins.d/10-get-sdk.sh
@@ -3,8 +3,8 @@
 set -x
 
 SDK_VERSION=24.4.1
-BUILD_TOOLS_VERSION=23.0.2
-COMPILE_SDK_VERSION=23
+BUILD_TOOLS_VERSION=26.0.0
+COMPILE_SDK_VERSION=26
 
 SDK=android-sdk-linux