BUG/MINOR: stats: fix capabilities and hide settings for some generic metrics

BUG/MINOR: stats: fix capabilities and hide settings for some generic metrics

Performing a diff on stats output before vs after commit 66152526
("MEDIUM: stats: convert counters to new column definition") revealed
that some metrics were not properly ported to to the new API. Namely,
"lbtot", "cli_abrt" and "srv_abrt" are now exposed on frontend and
listeners while it was not the case before.

Also, "hrsp_other" is exposed even when "mode http" wasn't set on the
proxy.

In this patch we restore original behavior by fixing the capabilities
and hide settings.

As this could be considered as a minor regression (looking at the commit
message it doesn't seem intended), better tag this as a bug. It should be
backported in 3.0 with 66152526.