Add MethodNotAllowed and Conflict exception classes

It is expected to recieve a 405 or a 409 from Nova, but novaclient presents
them as a generic ClientException. This patch adds MethodNotAllowed
and Conflict classes to represent these HTTP responses.

Change-Id: If89cee04ebd74daaa28ea30b5c57cdc63edc1551
100% test coverage for security groups and rules

This patch achieves full test coverage for security_group and
security_group_rules by:

- Fixing the arguments used in test_invalid_parameters_create
- Testing the __str__ and delete methods of SecurityGroupRule
- Adding a test for the ___str__ method of SecurityGroup

Change-Id: I9cfbc68761f158754aa4b339238d29cc587c91e1
Improve error messages for invalid --nic / --file.

Implemented by catching the valueerror thrown when unpacking a split to
two variables but the split string is not present.

Change-Id: I9930fe828c932e103fdad1b88c3434f097664f31
Merge "Add MethodNotAllowed and Conflict exception classes"
Provide nova CLI man page.

Resolves: bug 1130815
Blueprint: clients-man-pages

Provide basic but hopefully useful man page.

Change-Id: I6c520fa3acdb82dd564b758b9cdc448eecc6d6ce
Merge "100% test coverage for security groups and rules"
Merge "Provide nova CLI man page."
Merge "Improve error messages for invalid --nic / --file."