OS-531 Do not return None in infoblox_db

python returns None by default, remove unnecessary code from
infoblox_db.

Change-Id: Id72c6c8798a7d3e41a5c2e2ef5a65ad462bf0c9a
Merge pull request #11 from roman-verchikov/bp/infoblox-plugin-neutron

OS-531 Do not return None in infoblox_db
OS-425/OS-495, setup option 54 during network creation
Merge pull request #17 from Vegasq/OS-425

OS-425/OS-495, setup option 54 during network creation
OS-497 Fix EA names to match infoblox EA

EA were renamed from 'os_{ea_name}' to new names that
matches names declared in infoblox FS for VCO members.
Updated UT as well, and validated that new networks
created successfully on Juno.
Merge pull request #18 from bondar-pavel/rename-ea

OS-497 Fix EA names to match infoblox EA
OS-432 Update existing NIOS network on subnet create

In case
 a. user creates a subnet for shared or external network
 b. NIOS network with the same CIDR exists
Update existing network, rather than raising an error.

Change-Id: If9518c6fd7e6a18943c959339cfca72a504b8ee1