server: Remove max-buckets option and now max buckets is unlimited.

minio server max-buckets option removed. min-free-disk option is
now a flag.

pkg/fs/fs_test.go

@@ -36,7 +36,7 @@ func (s *MySuite) TestAPISuite(c *C) {
 		path, e := ioutil.TempDir(os.TempDir(), "minio-")
 		c.Check(e, IsNil)
 		storageList = append(storageList, path)
-		store, err := New(path, 0, 1000)
+		store, err := New(path, 0)
 		c.Check(err, IsNil)
 		return store
 	}