Mask out .cmake files

BUG=None
TEST=Run build_image and look at rootfs for any files left

Change-Id: I4983420fb17aae393c89b78ac93f655190241ee9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2681337
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: François Degros <fdegros@chromium.org>
Commit-Queue: François Degros <fdegros@chromium.org>
1 file changed