Originally reported in MDL-80646, but turns out to be a bug in stables too, so I'm splitting it out to this issue.

To replicate:

1. In 4.2 (not 4.3 and newer because you can't create instances like this any more there), go to a course
2. Click to add a new "External tool" activity
3. Set the Tool URL to "http://example.com"
4. Set the following in custom params:

   param=test

   param2=test2

5. Now, save and launch the tool (open the activity)
   Expected: No warnings flash on the view
   Actual: You'll see briefly a warning message or messages (as below) flash on the view, before the tool loads example.com (at which point the warning are no longer visible).

   Warning: Attempt to read property "ltiversion" on null in /moodle/next_development/www/mod/lti/locallib.php on line 1988

The culprit is this code. When a tool is configured manually, at the activity instance level, there is no 'ltiversion' property on the tool object. We should fix this to remove the warning. Whilst the bug cannot be easily seen in 4.3, the method still has the same problem there, and should be fixed there too.