Buildpack test already exists

[lv...@huawei.com]

Hi, all

User can't create the same name buildpack which just created with fail.

root@:~/apps# cf create-buildpack test buildpack-test 1

Creating buildpack test...

OK

Uploading buildpack test...

FAILED

Server error, status code: 400, error code: 290002, message: The buildpack upload is invalid: only zip files allowed

root@:~/apps# mv buildpack-test buildpack-test.zip

root@:~/apps# cf create-buildpack test buildpack-test.zip 1

Creating buildpack test...

OK

Buildpack test already exists

TIP: use 'cf update-buildpack' to update this buildpack

root@:~/apps#

i think it's better to allow creating buildpack rather than updating buildpack.

if buildpack creation fails, buildpack records stored in ccdb should be removed.

[Tao Deng]

I can reproduce it here. Before it is improved,  I recommend to delete the buildpack with 'cf delete-buildpack' command. 
Regards, 

Tao