Revert all GetObjectNInfo related PRs (#6398)

* Revert "Encrypted reader wrapped in NewGetObjectReader should be closed (#6383)"

This reverts commit 53a0bbeb5b.

* Revert "Change SelectAPI to use new GetObjectNInfo API (#6373)"

This reverts commit 5b05df215a.

* Revert "Implement GetObjectNInfo object layer call (#6290)"

This reverts commit e6d740ce09.

pkg/ioutil/ioutil.go

@@ -126,34 +126,3 @@ func (nopCloser) Close() error { return nil }
 func NopCloser(w io.Writer) io.WriteCloser {
 	return nopCloser{w}
 }
-
-// SkipReader skips a given number of bytes and then returns all
-// remaining data.
-type SkipReader struct {
-	io.Reader
-
-	skipCount int64
-}
-
-func (s *SkipReader) Read(p []byte) (int, error) {
-	l := int64(len(p))
-	if l == 0 {
-		return 0, nil
-	}
-	for s.skipCount > 0 {
-		if l > s.skipCount {
-			l = s.skipCount
-		}
-		n, err := s.Reader.Read(p[:l])
-		if err != nil {
-			return 0, err
-		}
-		s.skipCount -= int64(n)
-	}
-	return s.Reader.Read(p)
-}
-
-// NewSkipReader - creates a SkipReader
-func NewSkipReader(r io.Reader, n int64) io.Reader {
-	return &SkipReader{r, n}
-}