show vmess decode errors at warning level

[vcptr]

Currently core shows transport error at [Info] level:

2019/08/27 08:51:57 [Info] v2ray.com/core/proxy/vmess/outbound: tunneling request to tcp:v1.mux.cool:9527 via tcp:nov.meponse header > x509: certificate signed by unknown authority   

2019/08/27 08:54:44 [Info] [154526732] v2ray.com/core/app/proxyman/outbound: failed to process outbound traffic > v2ray.com/core/proxy/vmess/outbound: connection ends > v2ray.com/core/proxy/vmess/outbound: failed to read header > v2ray.com/core/proxy/vmess/encoding: failed to read response header > x509: certificate signed by unknown authority

Level Info/Debug are too verbose for users to find the root cause of a failing configuration. Show at warning level is more reasonable.

[rikkix]

If it is modified, the same type errors should also be modified.
I do not think this change is necessary and maybe it is not proper.

[vcptr]

same type errors do not need to be modified, they ARE on WARNING level.
I didn't offer the idea of changing this out of no where, I just find that all protocol's outbound error all goes to WARNING level but vmess.

EG for h2 protocol

v2ray-core/transport/internet/http/dialer.go

Line 104 in 1ab94fe

return nil, newError("failed to dial to ", dest).Base(err).AtWarning()

for kcp

v2ray-core/transport/internet/kcp/dialer.go

Line 57 in 4d23411

return nil, newError("failed to dial to dest: ", err).AtWarning().Base(err)

You can say that they are different, that's because raw vmess protocol doesn't need a wrapper layer, the encode/decode invokes connection directly. From a user's view, if a connection error occured, vmess protocol firstly raised up error from the decoder. Thus, they are the same type error of CONNECTION PROBLEMS, which should be warned.

[xiaokangwang]

I think treat this error as warning is reasonable since its effect is fully visible to user(Connection not established) and contain diagnoses information.