Stop reporting appveyor on_success, because it's noisy

Appveyor currently reports:

on_success:
- cmd: ... success
on_failure:
- cmd: ... failure

which is really noisy.

Travis currently reports:

  irc:
    ...
    on_success: change
    on_failure: change

which seems ok.

We should make Appveyor notifications more like Travis.

changed milestone to %Tor: 0.3.5.x-final in legacy/trac

added 034-backport in Legacy / Trac component::core tor/tor in Legacy / Trac milestone::Tor: 0.3.5.x-final in Legacy / Trac priority::medium in Legacy / Trac resolution::fixed in Legacy / Trac severity::normal in Legacy / Trac status::closed in Legacy / Trac tor-ci in Legacy / Trac type::defect in Legacy / Trac version::tor 0.3.4.1-alpha in Legacy / Trac labels

Please see my branch ticket27275 on https://github.com/teor2345/tor.git

I'm going to make sure that people actually want this change before I get it reviewed.

Trac:
Status: new to needs_information

nickm says yes, so I'll let this ticket go through the review process while others respond.

Trac:
Status: needs_information to needs_review

I agree with making appveyor quieter.

How far should I backport this?

.appveyor.yml was introduced in 0.3.4, so we can just cherry-pick backwards.

See my branch ticket27275-034, ci here: https://ci.appveyor.com/project/teor2345/tor/build/1.0.87

Trac:
Version: N/A to Tor: 0.3.4.1-alpha
Milestone: Tor: unspecified to Tor: 0.3.5.x-final
Keywords: N/A deleted, 034-backport added

Merged to 0.3.4 and forward!

Trac:
Resolution: N/A to fixed
Status: needs_review to closed

closed

moved from legacy/trac#27275 (moved)

added Bug label and removed 1 deleted label

added CI label and removed 1 deleted label