Fix the kwargs passed in as dict to listVirtualMachines

listVirtualMachines queried using tags needs the tags (key,value) to be
passed as a dictionary.

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
(cherry picked from commit c2840b93f5fd0d2d4e6dc4daa428b16a213fa8e7)

Signed-off-by: Prasanna Santhanam <tsp@apache.org>