meta-google: layer.conf: add zeus compatibility

OE-core master will be dropping warrior soon; zeus is the next release.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I70eb5509c6ef782e0832e97f4c4e4f4fb7d17841
diff --git a/conf/layer.conf b/conf/layer.conf
index bec624e..982339c 100644
--- a/conf/layer.conf
+++ b/conf/layer.conf
@@ -7,4 +7,4 @@
 BBFILE_COLLECTIONS += "google-layer"
 BBFILE_PATTERN_google-layer := "^${LAYERDIR}/"
 LAYERVERSION_google-layer = "1"
-LAYERSERIES_COMPAT_google-layer = "thud warrior"
+LAYERSERIES_COMPAT_google-layer = "warrior zeus"