Move publish-gear-endpoint logic to the platform

https://trello.com/card/2-make-publish-gear-endpoint-a-virtual-hook/50fc6814d58223727e0074e4/276

Move the logic for the `publish-gear-endpoint` logic from the hook script in each cartridge to the platform.

So far, only the v2 Ruby cartridge has removed the hook. This results in the following log entries in the broker:

```
2013-04-23 11:51:42.813 [DEBUG] Running publishers (pid:12494)
2013-04-23 11:51:43.708 [DEBUG] DEBUG: Output of parallel execute: [{:tag=>"5176ae0e7c53fd6b7d00002d", :gear=>"5176ade67c53fd30ce000001", :job=>{:cartridge=>"openshift-origin-node", :action=>"connector-execute", :args=>{"--with-app-uuid"=>"5176ade67c53fd30ce000001", "--with-app-name"=>"rack", "--with-container-uuid"=>"5176ade67c53fd30ce000001", "--with-container-name"=>"rack", "--with-namespace"=>"fooooooooooo", "--with-request-id"=>"5a77f4397cdb9c555aa0134540b30ac5", "--cart-name"=>"ruby-1.9", "--hook-name"=>"publish-http-url", "--input-args"=>"rack fooooooooooo 5176ade67c53fd30ce000001"}}, :result_stdout=>"rack-fooooooooooo.dev.rhcloud.com|10.114.109.112:35536\n", :result_stderr=>"", :result_exit_code=>0}, {:tag=>"5176ae0e7c53fd6b7d00002e", :gear=>"5176ade67c53fd30ce000001", :job=>{:cartridge=>"openshift-origin-node", :action=>"connector-execute", :args=>{"--with-app-uuid"=>"5176ade67c53fd30ce000001", "--with-app-name"=>"rack", "--with-container-uuid"=>"5176ade67c53fd30ce000001", "--with-container-name"=>"rack", "--with-namespace"=>"fooooooooooo", "--with-request-id"=>"5a77f4397cdb9c555aa0134540b30ac5", "--cart-name"=>"ruby-1.9", "--hook-name"=>"publish-gear-endpoint", "--input-args"=>"rack fooooooooooo 5176ade67c53fd30ce000001"}}, :result_stdout=>"5176ade67c53fd30ce000001@10.114.109.112:ruby;rack-fooooooooooo.dev.rhcloud.com", :result_stderr=>"", :result_exit_code=>0}], exitcode: 0, from: ip-10-114-109-112  (Request ID: 5a77f4397cdb9c555aa0134540b30ac5) (pid:12494)
2013-04-23 11:51:43.709 [DEBUG] DEBUG: MCollective Response Time (execute_parallel): 0.893650818s  (Request ID: 5a77f4397cdb9c555aa0134540b30ac5) (pid:12494)
2013-04-23 11:51:43.709 [DEBUG] Running subscribers (pid:12494)
2013-04-23 11:51:43.710 [DEBUG] Output of publisher - '{"5176ae0e7c53fd6b7d00002d"=>["'5176ade67c53fd30ce000001'='rack-fooooooooooo.dev.rhcloud.com|10.114.109.112:35536\n'"], "5176ae0e7c53fd6b7d00002e"=>["'5176ade67c53fd30ce000001'='5176ade67c53fd30ce000001@10.114.109.112:ruby;rack-fooooooooooo.dev.rhcloud.com'"]}' (pid:12494)
2013-04-23 11:51:43.711 [DEBUG] Output of publisher - '{"5176ae0e7c53fd6b7d00002d"=>["'5176ade67c53fd30ce000001'='rack-fooooooooooo.dev.rhcloud.com|10.114.109.112:35536\n'"], "5176ae0e7c53fd6b7d00002e"=>["'5176ade67c53fd30ce000001'='5176ade67c53fd30ce000001@10.114.109.112:ruby;rack-fooooooooooo.dev.rhcloud.com'"]}' (pid:12494)
```