NCLU Module: Improve performance by not operating on empty lines (#43024)

* Update nclu.py

Stop module from running `net` on empty commands.

* Update nclu.py

Updated the copyright date

* Update nclu.py

Returned metadata version to 1.1

* Update nclu.py

Fix indentation to be a multiple of 4.

* Create changelog fragment

changelogs/fragments/43024-nclu-empty-net-commands.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+- nclu - no longer runs net on empty lines in templates (https://github.com/ansible/ansible/pull/43024)

lib/ansible/modules/network/cumulus/nclu.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
 
-# (c) 2016-2017, Cumulus Networks <ce-ceng@cumulusnetworks.com>
+# (c) 2016-2018, Cumulus Networks <ce-ceng@cumulusnetworks.com>
 # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
 
 from __future__ import absolute_import, division, print_function
@@ -185,7 +185,8 @@ def run_nclu(module, command_list, command_string, commit, atomic, abort, descri
     # Run all of the net commands
     output_lines = []
     for line in commands:
-        output_lines += [command_helper(module, line.strip(), "Failed on line %s" % line)]
+        if line.strip():
+            output_lines += [command_helper(module, line.strip(), "Failed on line %s" % line)]
     output = "\n".join(output_lines)
 
     # If pending changes changed, report a change.