python Interpreter has hardcoded tmp path

On normal windows systems the python interpreter fails to start. The cause is that currently it tries to create all temporary scripts in C:\tmp which does not always exist.

This is caused by hard coded path in zeppelin-0.8.1\python\src\main\java\org\apache\zeppelin\python\PythonInterpreter.java:

public PythonInterpreter(Properties property) {
    super(property);
    try {
      File scriptFile = File.createTempFile("zeppelin_python-", ".py", new File("/tmp"));

....

If directory parameter is omitted (like in pyspark Interpreter) the system default from java.io.tmpdir is used, which is set by JVM.

Suggest fix is to remove directory parameter.

Workaround for Windows users with admin rights: Create c:\tmp directory.