cbbackupwrapper/cbbrestore fails after 6.5.0-2201 build due to python 3 migration

cbbackupwrapper is failing with below error starting 6.5.0-2201 build 

 
[71266] Failed to execute script cbbackupwrapper*17:17:06* Traceback (most recent call last):17:17:06 File "/home/couchbase/.pyenv/versions/3.6.7/lib/python3.6/base64.py", line 510, in _input_type_check*17:17:06* TypeError: memoryview: a bytes-like object is required, not 'str'17:17:06 17:17:06 The above exception was the direct cause of the following exception:17:17:06 17:17:06 Traceback (most recent call last):17:17:06 File "/home/couchbase/jenkins/workspace/couchbase-server-unix/couchbase-cli/cbbackupwrapper", line 287, in <module>17:17:06 File "/home/couchbase/jenkins/workspace/couchbase-server-unix/couchbase-cli/cbbackupwrapper", line 192, in getBuckets*17:17:06* File "/home/couchbase/.pyenv/versions/3.6.7/lib/python3.6/base64.py", line 540, in encodestring*17:17:06* File "/home/couchbase/.pyenv/versions/3.6.7/lib/python3.6/base64.py", line 527, in encodebytes*17:17:06* File "/home/couchbase/.pyenv/versions/3.6.7/lib/python3.6/base64.py", line 513, in _input_type_check*17:17:06* TypeError: expected bytes-like object, not str