[Admin utils] Also include fwaas.conf in default config files

Include /etc/neutron/fwaas.conf in default config files and verify
each file exists before using it in the admin util command.

Change-Id: Ibd53dcb0824eef89f03c27a9dea9a12aede1d370

vmware_nsx/shell/admin/plugins/common/constants.py

@@ -14,6 +14,7 @@
 
 # Default conf file locations
 NEUTRON_CONF = '/etc/neutron/neutron.conf'
+FWAAS_CONF = '/etc/neutron/fwaas.conf'
 NSX_INI = '/etc/neutron/plugins/vmware/nsx.ini'
 
 # NSX Plugin Constants

vmware_nsx/shell/nsxadmin.py

@@ -23,6 +23,7 @@ delete-security-groups, nsx neutron nsxv3 can be options
 TODO: Autocomplete command line args
 """
 
+from os import path
 import sys
 
 from neutron.common import config as neutron_config
@@ -59,12 +60,15 @@ def _init_cfg():
 
     # Make sure the default config files are used if not specified in args
     default_config_files = [constants.NEUTRON_CONF,
-                            constants.NSX_INI]
+                            constants.NSX_INI,
+                            constants.FWAAS_CONF]
+
     config_args = sys.argv[1:]
     if '--config-file' not in config_args:
         # Add default config files
         for file in default_config_files:
-            config_args.extend(['--config-file', file])
+            if path.exists(file):
+                config_args.extend(['--config-file', file])
 
     # Init the CONF and neutron config (Used by the core plugin)
     neutron_config.init(args=config_args)