Super minor: Close inputStream in SparkSubmitArguments

`Properties#load()` doesn't close the InputStream, but it'd be closed after being GC'd anyway...

Also changed file.getName to file, because getName only shows the filename. This will show the full (possibly relative) path, which is less confusing if it's not found.

Author: Aaron Davidson <aaron@databricks.com>

Closes #914 from aarondav/tiny and squashes the following commits:

db9d072 [Aaron Davidson] Super minor: Close inputStream in SparkSubmitArguments