Make it possible to restart WS in IDE if previous start failed

[garagatyi]

If user starts WS in IDE and it fails IDE doesn't have start button on top. So user has to refresh browser page to start WS again.
When user stops WS this button is shown.

Reproduction Steps:

1. Brake existing WS config, e.g. provide bad dockerfile as a source of machine. Or create new WS with broken config.
2. Open WS in IDE..
3. WS start will fail.

Expected behavior:

It is possible to press start button to restart WS.

Observed behavior:

There is no start button.

Che version: 5.0.0-Snapshot
OS and version: Ubuntu 16.04
Docker version: 12.04
Che install: Docker container

Additional information:

Problem started happening recently, didn't happen in an older version of Che: [No]
Problem can be reliably reproduced, doesn't happen randomly: [Yes]