Improve error message when openstack errors occur

[lnevers@bbn.com]

When an OpenStack error occurs during resource provisioning, such as the following:

(Slice urn:publicid:IDN+pgeni.gpolab.bbn.com+slice+expname) is in state 
       [Failed,None], err=resources failed to join: Error during join for unit: 
       1F54EE38 [1]: unable to create instance: exit code 1, \n"

The experimenter is not provided with insight into this error being transient and that the appropriate error handling action is to "try again!".

A clearer message would be helpful, especially if user is not aware of the ​https://geni-orca.renci.org/trac/wiki/orca-errors wiki page.

[ibaldin@renci.org]

In case of openstack resources may fail due to a number of problems some of which are transient and some of which are not.

For example, it can be a transient OpenStack? failure OR it can be because the user's image will not boot because of image construction errors. We have no way of distinguishing these and we cannot make error messages to be a paragraph long to explain all possible causes. This is why there is a web page and experimenters need to be adept enough and familiar enough with the documentation to look it up. It is much easier for us to update the web page, than it is to update error messages for all possible causes.

This is a 'won't fix'

[ahelsing@bbn.com]

How about saying that much in the error message:

'Resource failed: See ​https://geni-orca.renci.org/trac/wiki/orca-errors for possible solutions. Error message was......'

[ibaldin@renci.org]

This has been done.

[ahelsing@bbn.com]

Ilia already called this a 'wontfix'