This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
This commit removes the context as a param needed when calling methods
of HarnessNode. This change moves the context management inside
HarnessNode, aside from saving us a few lines, it makes the context
creation/timeout less error-prone.
In this commit, we put the context initialization inside
openChannelAndAssert, thus saving us a few lines and making sure the
context is always properly handled.
Because we now get one more update per channel when closing it, we need
to update our test that looks at the close notifications sent by the
SubscribeChannelEvent RPC.
