[VOL-2055] Use Tech Profile ID to differentiate downstream traffic scheduler

- CreateQueue / RemoveQueue / CreateSched / RemoveSched / FlowAdd updated to include
  tech_profile_id to select downstream scheduler.
- A DS scheduler is now identified by the tuple (pon, onu, uni, dir, tech_profile_id)
- voltha_protos v3.3.5 is now referred.
- Unit tests updated.
- VERSION updated.

Change-Id: I399bbb03aa33b61a02da10af0a40d354d44bd5cf
diff --git a/agent/Makefile.in b/agent/Makefile.in
index 3cbe94d..62f3ba3 100644
--- a/agent/Makefile.in
+++ b/agent/Makefile.in
@@ -42,7 +42,7 @@
 # This specifies the GIT tag in https://github.com/opencord/voltha-protos
 # repo that we need to refer to, to pick the right version of
 # openolt.proto and tech_profile.proto
-OPENOLT_PROTO_VER ?= v3.3.4
+OPENOLT_PROTO_VER ?= v3.3.5
 
 # Variables used for Inband build
 INBAND = "n"