Test disable dhcp
fixes for the rebase
Test disable dhcp

Added test Tempest test: Ability to disable DHCP, QA267.
Added sevaral test for security groups and dhcp.

Included all the remainding test but the multi-tenant ones.
Improved the functionality of the current scenario builder and
added several functions in relation to security groups.
Refactor from scenario builder
Added midokura scenario manager draft
fixed the comments of Daniel's code review
Merge remote-tracking branch 'upstream/master'
Merge pull request #10 from alvico/rebase_sg

Rebase sg
Removed breakpoints from manager.py
Merge pull request #11 from danielmellado/master

Updated Scenario Builder