Update the Makefile to use the new testenv syntax.
Update the Makefile to use the new testenv syntax.

Problem:
- TestEnv now requires a configuration file while deleting stacks.

Solution:
- Remove the `--name` parameter from the `testenv delete` commands.

michaeldayreads/marathon-bigip-ctlr,michaeldayreads/marathon-bigip-ctlr,michaeldayreads/marathon-bigip-ctlr