Fix Aleth presence on ethernodes.org

[chfast]

https://ethernodes.org/client/aleth

The Aleth version is not available there. Fix it to get information which Aleth versions are in use on the Ethereum network.

Ethernodes.org contact point: @ppratscher.

[peterbitfly]

It looks like our semver library is not able to parse the version string in the client id of aleth.

Aleth uses the following format: aleth/1.5.2+commit.00fd8416.dirty/linux/gnu7.4.0/relwithdebinfo while most other nodes use the following: Geth/v1.9.6-stable-bd059680/linux-amd64/go1.11.5 or Parity-Ethereum/v2.6.1-beta-7bfbe41-20190814/x86_64-linux-gnu/rustc1.36.0

It will be sufficient to change 1.5.2 to v1.5.2 for our crawler to pick up the version number.

[gumb0]

We can make the fix in

aleth/libwebthree/WebThree.cpp

Lines 61 to 66 in a3cdc87

	std::string WebThreeDirect::composeClientVersion(std::string const& _client)
	{
	const auto* buildinfo = aleth_get_buildinfo();
	return _client + "/" + buildinfo->project_version + "/" + buildinfo->system_name + "/" +
	buildinfo->compiler_id + buildinfo->compiler_version + "/" + buildinfo->build_type;
	}

(but apparently it won't help with getting info from currently run clients that won't update)

[halfalicious]

@gumb0 / @chfast Should we mark this as help wanted since the fix is understood and trivial?

[chfast]

Ok, so the task is to change the reported version format to follow geth/parity/other clients. We don't care about previous versions at this point.

[gumb0]

It's one letter fix, let's just do it :-)

(I will do it some time soon, if no one does before me)