Fix a bug when dragging and dropping a local project into the applicat...

...ionViewer.

If there is already a cloud application with the same name as the local project, the cloud application will be deleted and replaced by the local project, which is "not yet deployed". 

*Fig1* drag and drop local project with the same name
![drag&drop](https://cloud.githubusercontent.com/assets/7316500/4006332/71af4820-29a8-11e4-96bc-e2fd9dc42aae.PNG "drag and drop local project with the same name")

*Fig2* existed cloud application is replaced
![replaced](https://cloud.githubusercontent.com/assets/7316500/4006543/87b5025e-29ad-11e4-81f8-85b10d4e603b.PNG "existed cloud application is replaced")

There should better be a warning message and not delete the cloud application which already exists.

*Fig3* better jump out a warning message
![warning](https://cloud.githubusercontent.com/assets/7316500/4006594/9225eb8e-29af-11e4-805e-772ffed8c37a.PNG "better jump out a warning message")