Insteon: Do Not Attempt to Clear the Active Message if it Does Not Exist in Parsing all_link_complete

Fixes the bug that may occur when using the old deprecated "complete linking as responder" voice command.

Fixes hollie/misterhouse#407
Merge pull request #415 from krkeegan/fix_issue_407

Insteon: Do Not Attempt to Clear the Active Message if it Does Not Exist in Parsing all_link_complete