Fix the typo, should be defaults

Change-Id: I7fd5c266a5d93ca9a65867d1856ede5c027f873e
diff --git a/voltha/values.yaml b/voltha/values.yaml
index 979119f..c8bf4c3 100644
--- a/voltha/values.yaml
+++ b/voltha/values.yaml
@@ -81,7 +81,7 @@
   timeout_request: '{{ .Values.defaults.rw_core.timeout }}'
 
 ofagent:
-  log_level: '{{ .Values.default.log_level }}'
+  log_level: '{{ .Values.defaults.log_level }}'
 
 
 # Define Docker images to be used