CLOUDSTACK-8001: test_add_remove_network.py - Tag invalid test case as invalid

Signed-off-by: SrikanteswaraRao Talluri <talluri@apache.org>
CLOUDSTACK-7993: Code enhancement - test_egress_fw_rules.py - Removing unncessary waits

Signed-off-by: SrikanteswaraRao Talluri <talluri@apache.org>
CLOUDSTACK-7979 : Fixed the script 'test_security_groups.py' - Zone Network Type Information should to be passed to VirtualMachine create method
CLOUDSTACK-7563: Fix potential NPE in checking answer

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>