Travis build failing due to broken plugin test

[outofcoffee]

The Travis build is failing due to a broken test.

The cause is:

type":"PluginNotFoundException","errorCode":12002,"message":"Plugin does not exist: 1"

The test assumes a predicable ID for the created plugin but this is not so. Need to update test to use the response of listing plugins to get the right ID.

[outofcoffee]

Fixed in b3f5eff. CI build: https://travis-ci.org/apiman/apiman-cli/builds/125208509