Rewrite error handling

Execution will now continue if some API calls fail, e.g. if a device
doesn't support lookup of certain properties.

Signed-off-by: John Else <john.else@citrix.com>
Don't get fan speed

Signed-off-by: John Else <john.else@citrix.com>
Add comments

Signed-off-by: John Else <john.else@citrix.com>
Get device utilisation

Signed-off-by: John Else <john.else@citrix.com>
Add newline

Signed-off-by: John Else <john.else@citrix.com>
Get device ECC mode

Signed-off-by: John Else <john.else@citrix.com>
Reformat how the data is printed

Signed-off-by: John Else <john.else@citrix.com>