check-code: Only call check-code if __name__ = "__main__".
This changeset moves the code that actually executes something to the
"if __name__ = '__main__'" section to allow the file to be imported as
a module.
#!/bin/sh
hg init
echo a > a
hg ci -Am t
hg mv a b
hg ci -Am t1
hg debugrename b
hg mv b a
hg ci -Am t2
hg debugrename a
echo % test with --rev
hg debugrename --rev 1 b