* fixes ZEN-14460, disable creation of zenpack via the ui, add via CLI

This disables zenpack creation via the UI. It is problematic because of the non-sticky sessions in Europa. Zenpacks can be created via the CLI with the create command. Existing zenpacks can be install on the CLI in linked mode as well.

```
Creating a new zenpack (installs in link mode)
dgarcia@dgarcia-desktop:~/src/europa/src/golang/src/github.com/control-center/serviced⟫ ./serviced service run zope zenpack create /home/zenoss/ZenPacks.zenoss.FML
I0930 11:26:21.866995 20263 server.go:341] Connected to the control center at port 10.87.120.128:4979
....
INFO:zen.ZenPackCMD:installing zenpack ZenPacks.zenoss.FML; launching process
2014/09/30 16:26:46.652290 Registrar received 1 events
2014-09-30 16:26:48,226 INFO zen.ZPLoader: Loading /home/zenoss/ZenPacks.zenoss.FML/ZenPacks/zenoss/FML/objects/objects.xml
2014-09-30 16:26:48,227 INFO zen.AddToPack: End loading objects
2014-09-30 16:26:48,227 INFO zen.AddToPack: Processing links
2014-09-30 16:26:48,319 INFO zen.AddToPack: Loaded 0 objects into the ZODB database
2014-09-30 16:26:48,354 INFO zen.HookReportLoader: Loading reports from /home/zenoss/ZenPacks.zenoss.FML/ZenPacks/zenoss/FML/reports
2014/09/30 16:26:48.561769 Registrar received 2 events
2014/09/30 16:26:50.647265 Registrar received 1 events
I0930 11:26:55.394324 20263 shell.go:207] Committing container
```