Backport/2.7/46044 Make puppet module useable on puppet 6 (#48871)

* Make puppet module useable on puppet 6 (#46044)

The unused ignorecache setting has been removed and so you
can't run puppet through this module anymore.

See PUP-8533 / https://tickets.puppetlabs.com/browse/PUP-8533
(cherry picked from commit 475d69da69)

* changelog

changelogs/fragments/46044-puppet-puppet6-fix.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+- Puppet module remove ``--ignorecache`` to allow Puppet 6 support

lib/ansible/modules/system/puppet.py

@@ -216,7 +216,7 @@ def main():
 
     if not p['manifest'] and not p['execute']:
         cmd = ("%(base_cmd)s agent --onetime"
-               " --ignorecache --no-daemonize --no-usecacheonfailure --no-splay"
+               " --no-daemonize --no-usecacheonfailure --no-splay"
                " --detailed-exitcodes --verbose --color 0") % dict(base_cmd=base_cmd)
         if p['puppetmaster']:
             cmd += " --server %s" % pipes.quote(p['puppetmaster'])