RIBCL is broken with requests (2.11.0)

[Shivanand Tendulker]

With requests library 2.11.0, ribcl operations fails

Sample Program:-
----------------
import proliantutils.ilo.client as client
import proliantutils.ilo.ris as ris

obj = client.IloClient("10.10.1.56", "Administrator", "12iso*help")

print 'get_host_power_status %(stat)s.' % obj.get_host_power_status()

Error o/p
-------------
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/stack/proliantutils/proliantutils/ilo/client.py", line 70, in __init__
    self.model = self.ribcl.get_product_name()
  File "/opt/stack/proliantutils/proliantutils/ilo/ribcl.py", line 328, in get_product_name
    'GET_PRODUCT_NAME', 'SERVER_INFO', 'read')
  File "/opt/stack/proliantutils/proliantutils/ilo/ribcl.py", line 311, in _execute_command
    d = self._request_ilo(xml)
  File "/opt/stack/proliantutils/proliantutils/ilo/ribcl.py", line 124, in _request_ilo
    raise exception.IloConnectionError(e)
proliantutils.exception.IloConnectionError: Header value 182 must be of type str or bytes, not <type 'int'>

Requests library expects 'Content-length' value to be str or bytes type. but we pass it as int.
https://github.com/openstack/proliantutils/blob/master/proliantutils/ilo/ribcl.py#L104