RM6541 ip_availability script: fix unused count

Removed deallocated, reusable IP count from unused count because the
number of deallocated, reusable IPs was already included as part of
the subnet's size.
RM6541: ip_availabilty script: fixes _cidr filter

Replaced _cidr filter on IPv6 addresses and 10.% addresses by
checking for ip_version = 4 and network_id = all 0's.
Magic numbers removed
Using kw params as Python intended
Removing string formating for better clarity
Fix related to 5702b7, db_api related tests
Fixes RM6714: move IPAddress filter to ON clause of JOIN (used IPs)
Removing unnecessary __new__ method and super() logic
Removing unnecessary Mock.mock()
Merge pull request #134 from asadoughi/master

RM6541: ip_availability script minor fixes
Flake8 fixes and removing list param default
Allows manual reset of deallocate_at for admins

Done through PUT to /ip_addresses with "reset_allocation_time": true in the
body.

A few modifications were done to base_tests to support the admin context.

Had to prevent admin_roles from being loaded on context.

Removed the DEFAULT_ROUTE thing for great justice!

Non-admin access will raise HTTPForbidden.

Created _create_patch for the extra patching love.

RM6300
Merge pull request #133 from roaet/add_manual_deallocate_reset

Allows manual reset of deallocate_at for admins
Removed the remaining string formating
Removing accidental extra line on EOF
Merge pull request #136 from insequent/refactor_ipam_tests

Refactor ipam tests
Fixes #137

Removes lazy="joined" on routes into subnets. Instead, groups routes in
explicitly when necessary.
Merge pull request #138 from Cerberus98/master

Fixes #137
Fixes #75

IP addresses in subnets marked as "do_not_use" are now ignored
successfully.
Merge pull request #140 from Cerberus98/issue75

Fixes #75