[#1963] Improve error messages on datastore upload page.

 * Show the log even when the job has errored.
 * Split up parts the flash error message to the status table
 * If the error contains more detailed job info, show that in the status
   table. Add the raw response to the table but hidden

also requires https://github.com/ckan/ckan-service-provider/pull/19 and https://github.com/ckan/datapusher/pull/51.

All three of these combined gives the slightly more user friendly.
![datastore_error](https://cloud.githubusercontent.com/assets/241130/4773921/d6310474-5ba7-11e4-83b0-08e3c024861f.png)