Existing MC_HOSTS_<alias> was incorrectly placed
inside s3Config initialization code path which
leads to a situation where we loose the URL path
information.
Fixes#2364
The probe package is no longer available in the Minio server
repo. This change just moves probe from the vendor directory to its
own dir under `pkg`.
This is a maintenance fix.
TLSConfig should be allocated regardless of the
URL scheme so that the re-direction works properly.
Without this change if a server is configured with
self signed certs redirection would fail with
```
x509: certificate signed by unknown authority
```
Allocate TLSConfig always with default values.
