hdfs-mount/FileHandleWriter.go expects /var/ to be writable.

[gwlperl]

Please consider the TODO below.

/var is only ever going to be writable by root, except in very insecure environments. If this was trying to make something like /var/hadoop/hdfs-mount then we could deal with it by creating the "/var/hadoop" directory and making it writable by the user we are building as. As it is, it'll only work in a docker container.

hdfs-mount/FileHandleWriter.go

37		stageDir := "/var/hdfs-mount" // TODO: make configurable
38		if ok := os.MkdirAll(stageDir, 0700); ok != nil {
39			Error.Println("Failed to create stageDir /var/hdfs-mount, Error:", ok)
40			return nil, ok
41		}