Move _convert_to_nsx_transport_zones into nsx_utils

This routine does not need to be in the plugin class. This patch
transforms it into an utility method and adds unit tests to
increase coverage.

Change-Id: Ieacc36e729c4db90efd33944f7cf05dcb30e1de9
Closes-Bug: 1340210
NSX: Remove unneed call to _ensure_default_security_group

This patch removes an unneeded call to _ensure_default_security_group
which does not need to be called in create_security_group_rule_bulk()
as one would need to call get_security_groups() to look up the uuid
of the default security group which be would created it for us, BOOM!

Change-Id: I628a94c7ea9553dcefa68fa956f25244f0abbb18
Closes-bug: 1340536
Initialize RpcProxy objects correctly

RpcProxy class is used as base in classes with multiple inheritance
(ex. MeteringAgent). To initialize objects of such classes correctly
every constructor should call its base constructor via super().__init__()

Closes bug 1332788

Change-Id: I00ef804b6ee6c73dec3e177202bb85311e3e2b10
Fix incorrect downgrade

In downgrade of migration b7a8863760e_rm_cisco_vlan_bindin is used
Integer type with parameter display_width. Integer should be used
without any parameters.

Closes-bug: #1346245

Change-Id: Ic444af81ed3ec25116d2171ab465ce473cba8113
Correct LOG.debug use

The commit b3202c3283597de031572e0ede082237487d8110 used:

  LOG.debug("...%(key1)s...", key1=value1)

which  is not supported, this change ues instead:

  LOG.debug("...%(key1)s...", {"key1": value1})

Change-Id: I9bd63c27ca8acf89284399fda8cd74c82906113b
Merge "Correct LOG.debug use"
Merge "Initialize RpcProxy objects correctly"
Merge "Fix incorrect downgrade"
Merge "NSX: Remove unneed call to _ensure_default_security_group"
Merge "Move _convert_to_nsx_transport_zones into nsx_utils"