prebuilt.conf: updating FULL_BINHOST

Change-Id: Iacd614807631f411583dc325af467304aafe1594
diff --git a/overlay-kevin64/prebuilt.conf b/overlay-kevin64/prebuilt.conf
index e308f1a..8462a72 100644
--- a/overlay-kevin64/prebuilt.conf
+++ b/overlay-kevin64/prebuilt.conf
@@ -1 +1 @@
-FULL_BINHOST="gs://chromeos-prebuilt/board/kevin64/full-R78-12427.0.0-rc2/packages/"
+FULL_BINHOST="gs://chromeos-prebuilt/board/kevin64/full-R78-12427.0.0-rc3/packages/"