spacewalk-clone-by-date fails with error "AttributeError: type object 'datetime.datetime' has no attribute 'strptime'"

Issue

• On Red Hat Satellite 5.6 spacewalk-clone-by-date fails when using configuration file.
  For example:

  # cat clone-03Nov15.cfg 
  {
  "assumeyes":true,
  "to_date": "2015-11-03",
  "skip_depsolve":false,
  "security_only":false,
  "blacklist": {
               },
  "removelist": {
               },
  "channels":[
              {
              "rhel-x86_64-server-7": "rhel-x86_64-server-7_03Nov15"  
              }
            ]
  }
  

  The spacewalk-clone-by-date fails to clone channel.

  # spacewalk-clone-by-date --config="/path-to/clone-03Nov15.cfg" --username "admin" --password "password"
  Reading repository information.
  Using issue_date.
  By continuing the following will be cloned:
  rhel-x86_64-server-7 -> rhel-x86_64-server-7_03Nov15  (673/675 Errata)
  Copying repodata, please wait.
  Solving Dependencies (4311): 
  ######################################## - complete
  Processing Dependencies:
  ########################################Traceback (most recent call last):
  File "/usr/bin/spacewalk-clone-by-date", line 253, in ?
    sys.exit(abs(main() or 0))
  File "/usr/bin/spacewalk-clone-by-date", line 243, in main
    return cloneByDate.main(args)
  File "/usr/share/rhn/utils/cloneByDate.py", line 177, in main
    cloner.create_channels(options.skip_depsolve)
  File "/usr/share/rhn/utils/cloneByDate.py", line 302, in create_channels
    self.dep_solve(nvreas, labels=(to_create.keys() + [self.src_parent]))
  File "/usr/share/rhn/utils/cloneByDate.py", line 385, in dep_solve
    self.__dep_solve(nvrea_list)
  File "/usr/share/rhn/utils/cloneByDate.py", line 397, in __dep_solve
    self.process_deps(dep_results)
  File "/usr/share/rhn/utils/cloneByDate.py", line 429, in process_deps
    added_nevras = added_nevras + cloner.process_deps(needed)
  File "/usr/share/rhn/utils/cloneByDate.py", line 523, in process_deps
    if not self.to_date or (self.to_date and \
  AttributeError: type object 'datetime.datetime' has no attribute 'strptime'