fix None type bug (#20)

* fix None type bug

* add change log fragment

Author: rainerleber

changelogs/fragments/0020-fix_sap_control_exec.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - fix a bug where some commands produces no output which cause to crash the module.

plugins/modules/sap_control_exec.py

@@ -384,7 +384,10 @@ def main():
         result['msg'] = 'Something went wrong connecting to the SAPCONTROL SOAP API.'
         module.fail_json(**result)
 
-    returned_data = recursive_dict(conn)
+    if conn is not None:
+        returned_data = recursive_dict(conn)
+    else:
+        returned_data = conn
 
     result['changed'] = True
     result['msg'] = "Succesful execution of: " + function