Fixes around variable usage

servers_client: used post request instead of get for get all tenants
object_client: missing self before a method
snapshots_client: method redeclaration
testboto: wrong variable name
test_ec2_instance_run: missing cls
test_ec2_network.py: missing self
test_server_metadata.py: meta dict was not in use
test_authorization.py: unused variables
test_live_block_migration: tricky error handling
base: unused variables
test_network_basic_ops: unused variables

Change-Id: I5fedf2fc2de5724614ade9cb5af14dd75e684205
Merge "Fixes around variable usage"