VOL-2241:  Python 3 migration

 - rename adapter class file and remove unneeded __init__ to make imports work without major rearrange
 - venv and Dockerfile fixups needed for new pyvoltha (cannot install old first)
 - clean up yaml config file as it contained empty entries that failed to parse
 - clean up imports
 - remove itervalues iter*
 - convert to list() as needed
 - test with python 3.6
 - skip non-dict items in tcont loop
 - update to voltha-protos 2.1.0
 - migrate socketserver and simplehttpserver to python3 import

Change-Id: Id8efa72b6796a3055b1927716503a33544bb6548
diff --git a/python/adapters/brcm_openomci_onu/omci/brcm_vlan_filter_task.py b/python/adapters/brcm_openomci_onu/omci/brcm_vlan_filter_task.py
index eaa3176..2589247 100644
--- a/python/adapters/brcm_openomci_onu/omci/brcm_vlan_filter_task.py
+++ b/python/adapters/brcm_openomci_onu/omci/brcm_vlan_filter_task.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 #
 
+from __future__ import absolute_import
 import structlog
 from pyvoltha.adapters.extensions.omci.tasks.task import Task
 from twisted.internet import reactor
@@ -21,8 +22,8 @@
 from pyvoltha.adapters.extensions.omci.omci_defs import ReasonCodes, EntityOperations
 from pyvoltha.adapters.extensions.omci.omci_me import \
     VlanTaggingOperation, VlanTaggingFilterDataFrame, ExtendedVlanTaggingOperationConfigurationDataFrame
-from adapters.brcm_openomci_onu.uni_port import UniType
-from adapters.brcm_openomci_onu.pon_port import DEFAULT_TPID
+from uni_port import UniType
+from pon_port import DEFAULT_TPID
 
 RC = ReasonCodes
 OP = EntityOperations