Change default machine name to che

[TylerJewell]

Improved an error message and changed the default docker-machine to be named "che". This solves some issues with Windows systems that have previously run a docker machine named "default".

[TylerJewell]

@eivantsov, @riuvshin - wdyt.

[vparfonov]

ok

[riuvshin]

OK if you've tested this, because we don't have windows to test

[TylerJewell]

QA needs windows environments to test.

[riuvshin]

OK

[vparfonov]

Tested on my machine Windows 10.
$ docker --version
Docker version 1.9.1, build a34a1d5
Can confirm working well.
After stopping Che Workspace Master VM Che not removed and after start again images don't pulling again.

But met problem with starting Workspace Agent not enough time
machine.ws_agent.max_start_time_ms=60000 propose increase this value 4-5 times.

[ghost]

worked for me