Using released apps and releasing voltha-onos 5.0.1 for VOLTHA 2.8

Change-Id: I63361ba676f1f0d8849e775c9b33378f03ad744d
diff --git a/Dockerfile.voltha-onos b/Dockerfile.voltha-onos
index 97d42ae..1555687 100644
--- a/Dockerfile.voltha-onos
+++ b/Dockerfile.voltha-onos
@@ -34,7 +34,7 @@
 
 
 # Unpack and install specific apps from download stage
-FROM onosproject/onos:2.5-latest as install
+FROM onosproject/onos:2.5.2 as install
 
 # The ENV settings must be replicated below as they are not shared between stages
 ENV ONOS=/root/onos
@@ -58,7 +58,7 @@
 
 
 # Create the final image coping over the installed applications from the install stage
-FROM onosproject/onos:2.5-latest
+FROM onosproject/onos:2.5.2
 
 # The ENV settings must be replicated below as they are not shared between stages
 ENV ONOS=/root/onos