Remove legacy error reporting.

Only send errors to Sentry. Pretend ever error is a shiny new one.
We should remove the fixed status at some point.

Change-Id: I1ae79eca54a417182cdf1ecb560b59c1674be549
Fixes-Issue: CLIENT-475
Reviewed-on: http://gerrit.dmdirc.com/3329
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager