[WIP] all: Update go-ethereum dependency to 1.9.7

[chadsr]

This PR bumps the go-ethereum dependency to v1.9.7, the latest release.

Changes are the result of these steps:

• Bumped go.mod go-ethereum to v1.9.7
• go mod verify
• go mod tidy
• go mod vendor
• make vendor

My main motivation for this PR is that with go-ethereum 1.9.7, I can resolve #1799.
If any steps are not preferred ways to maintain modules here (like tidying), please let me know.

[janos]

Hi, thanks for the upgrade and detailed steps that were done. We have a slightly different way to vendor libraries in order to copy forked c libraries from dependant packages. They are showing as deleted in this pr. There is a Makefile rule vendor that takes care of these cases. It should be enough just to call make vendor and commit changes.

[chadsr]

Hm, something seems to be broken/flakey with karalabe/usb/libusb still.

I've updated leveldb and also karalable/usb, which resolved some issues, but i'm still getting:
ERROR[11-13|10:11:56.147] Failed to enumerate USB devices hub=trezor vendor=21324 failcount=1 err="failed to initialize libusb: libusb: unknown error [code -99]"

Will do some more investigating to see what went wrong.

[chadsr]

My priorities had been rearranged somewhat, but now i'm back to looking at this.

I'm finding it hard to track down the cause of the remaining failing test. It appears to be this regex check failing to match on the stdout output. I assume it expects a hash, but the value is in fact null.

Input is welcome from someone with a more complete overview of the swarm codebase :)