Smarter restore logic for closing channels

[pm47]

If the closing type is known:

• there is no need to watch the funding tx because it has already
  been spent and the spending tx has already reached min_depth
• there is no need to attempt to publish transactions for other
  type of closes.

[codecov-io]

Codecov Report

Merging #1015 into master will increase coverage by 0.34%.
The diff coverage is 44.82%.

@@            Coverage Diff            @@
##           master   #1015      +/-   ##
=========================================
+ Coverage   80.15%   80.5%   +0.34%     
=========================================
  Files          98      98              
  Lines        7554    7647      +93     
  Branches      296     301       +5     
=========================================
+ Hits         6055    6156     +101     
+ Misses       1499    1491       -8

Impacted Files	Coverage Δ
...c/main/scala/fr/acinq/eclair/channel/Channel.scala	83.47% <0%> (+0.46%)	⬆️
...c/main/scala/fr/acinq/eclair/payment/Auditor.scala	88.37% <100%> (ø)	⬆️
...c/main/scala/fr/acinq/eclair/channel/Helpers.scala	94.48% <92.3%> (+0.92%)	⬆️
...scala/fr/acinq/eclair/payment/PaymentRequest.scala	90.45% <0%> (-1.61%)	⬇️
...-core/src/main/scala/fr/acinq/eclair/io/Peer.scala	75.25% <0%> (+0.33%)	⬆️
...src/main/scala/fr/acinq/eclair/router/Router.scala	86.72% <0%> (+0.94%)	⬆️
...ir-core/src/main/scala/fr/acinq/eclair/Setup.scala	66.21% <0%> (+2.08%)	⬆️
.../acinq/eclair/blockchain/bitcoind/ZmqWatcher.scala	97.05% <0%> (+3.92%)	⬆️
...clair/blockchain/electrum/ElectrumClientPool.scala	78.49% <0%> (+4.3%)	⬆️
... and 2 more