one_vm: fix syntax error when creating VMs with a more complex template

with more complex templates that make use of quoted strings the new
"render" method fails to produce a template that is accepted by
OpenNebula.  ==> escape double quotes in strings to make OpenNebula
happy again.

I also tested whether newlines need to be escaped, looks like they are
fine as they are.

Fixes ansible-collections#6225

changelogs/fragments/6294-fix-one_vm-instantiation.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - one_vm - fix syntax error when creating VMs with a more complex template (https://github.com/ansible-collections/community.general/issues/6225)

plugins/module_utils/opennebula.py

@@ -52,6 +52,9 @@ def recurse(to_render):
                 for item in value:
                     yield '{0:}=[{1:}]'.format(key, ','.join(recurse(item)))
                 continue
+            if isinstance(value, str):
+                yield '{0:}="{1:}"'.format(key, value.replace('"', '\\"'))
+                continue
             yield '{0:}="{1:}"'.format(key, value)
     return '\n'.join(recurse(to_render))
 

tests/unit/plugins/module_utils/test_opennebula.py

@@ -75,6 +75,14 @@
             NIC=[NAME="NIC1",NETWORK_ID="1"]
         ''').strip()
     ),
+    (
+        {
+            'SCHED_REQUIREMENTS': 'CLUSTER_ID="100"',
+        },
+        textwrap.dedent('''
+            SCHED_REQUIREMENTS="CLUSTER_ID=\\"100\\""
+        ''').strip()
+    )
 ]