httpRespToErrorResponse() usually reads the http response when
the http error code is not expected to parse the json error
response in the http body, however it was never properly closing
the connection. This PR fixes the behavior.
Two handlers are added to admin API to enable profiling and disable
profiling of a server in a standalone mode, or all nodes in the
distributed mode.
/minio/admin/profiling/start/{cpu,block,mem}:
- Start profiling and return starting JSON results, e.g. one
node is offline.
/minio/admin/profiling/download:
- Stop the on-going profiling task
- Stream a zip file which contains all profiling files that can
be later inspected by go tool pprof
