Ensure proper error when fetch_url returns status -1

When using a file:// or ftp:// URL the normal provisions that a non-200 status code means error have been disabled.
But the common error status -1 from fetch_url is not properly returning an error message.
This fix ensures that if the status code returns -1, we return a proper error message.

This fixes #3563

lib/ansible/modules/network/basics/get_url.py

@@ -226,10 +226,14 @@ def url_get(module, url, dest, use_proxy, last_mod_time, force, timeout=10, head
     if info['status'] == 304:
         module.exit_json(url=url, dest=dest, changed=False, msg=info.get('msg', ''))
 
-    # create a temporary file and copy content to do checksum-based replacement
+    # Exceptions in fetch_url may result in a status -1, the ensures a proper error to the user in all cases
+    if info['status'] == -1:
+        module.fail_json(msg=info['msg'], url=url, dest=dest)
+
     if info['status'] != 200 and not url.startswith('file:/') and not (url.startswith('ftp:/') and info.get('msg', '').startswith('OK')):
         module.fail_json(msg="Request failed", status_code=info['status'], response=info['msg'], url=url, dest=dest)
 
+    # create a temporary file and copy content to do checksum-based replacement
     if tmp_dest != '':
         # tmp_dest should be an existing dir
         tmp_dest_is_dir = os.path.isdir(tmp_dest)