print_exeception crashes

I get errors if in errors
```
    xt.print_exception(
    ~~~~~~~~~~~~~~~~~~^
        source_msg="Exception in thread " + get_proc_proxy_name(self)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
TypeError: _print_exception() got an unexpected keyword argument 'source_msg'
```

xonsh.tools.print_exception has added an extra parameter.