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.
New host list format when listing several hosts
```
myminiopublic : http://localhost:9000
myminios : https://minio1.duckdns.org:... Q3AM3UQ867SPQQA43P2F zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG S3v4
testazure : http://172.17.0.7:9000 myazureac Gh5543wekitnifILbZam1KYY3TGlswRminio1... S3v4
```
New host list format when listing one host:
```
azure: http://localhost:9000 myazureac Gh5543wekitnifILbZam1KYY3TGlswRminio1u7BJ86wekitnifILbZam1K== S3v4
```
