BMC pane renders a full HTML error response from proxy BMC calls
My host has a BMC proxy assigned that's giving out a Ruby error response in HTML along the lines of:
LoadError at /bmc/10.1.1.1/chassis/power/status
no such file to load -- rubyipmi
When I'm viewing the host page in Foreman, the BMC tab is rendering the full HTML response from the proxy inline. Since the proxy error response contains CSS too, this is creating a huge mess of the Foreman UI.
Foreman probably shouldn't pass HTML errors along to the browser when the proxy fails.
Fixes #2619 - don't display full output from proxy
Proxy output is logged alongside with backtrace of exception. We display
only exception message in UI.