fixing flake in legacy code around app manifest creation
fixing flake in legacy code around app manifest creation

Since these tests all used the same app name, directory, and actually
wrote to disk; when the tests would run in parallel, the AfterEach file
cleanup could delete a written manifest file while another test is
running. This would cause a "no such file or directory" to occur during
an 'os.Create'.

Instead, have each test use a different app name ensuring that the
filename will always be unique. Also, since this is the legacy code,
changing the test is safer than changing the production code.

cloudfoundry/cli,cloudfoundry/cli,cloudfoundry/cli