pin precheck fails with an exception when using --template-def

[urish]

The error:

Traceback (most recent call last):
  File "/home/uri/p/tt10-oscillating-bones/tt/precheck/precheck.py", line 223, in main
    check()
  File "/home/uri/p/tt10-oscillating-bones/tt/precheck/precheck.py", line 211, in <lambda>
    lambda: pin_check(gds_file, lef, template_def, top_module, uses_3v3),
                                                               ^^^^^^^^
NameError: cannot access free variable 'uses_3v3' where it is not associated with a value in enclosing scope

This happens since uses_3v3 is only defined when args.template_def is None