[2.6] Clean up after ansible-connection if failure occurred in start() (#45929)

(cherry picked from commit 0d143ed)

Co-authored-by: Nathaniel Case <this.is@nathanielca.se>

bin/ansible-connection

@@ -263,6 +263,8 @@ def main():
 
                     if rc == 0:
                         process.run()
+                    else:
+                        process.shutdown()
 
                     sys.exit(rc)