Rollback 318 then bump to 319, in a squash. ;)

Revert "update ccache to 3.1.8"

Were upgrading to 319 and i dont trust git binary merges.

This reverts commit 57d0d8dca0dea00efaa43849af8bc7129e6667cf.

Updated ccache to 3.1.9

Change-Id: I1245013758d9874c49744e2bb6185fb682122834