Fix duplicate function definition in _remove_readonly

[ScuttleBot]

PR #74 introduced a duplicate function definition that causes an IndentationError, breaking all benchmark registrations:

File "/root/skill/scripts/lib_agent.py", line 370
    def _remove_readonly(func, path, _):
    ^
IndentationError: expected an indented block after function definition on line 369

This removes the duplicate line and the errant func(path) call that was outside the try/except block.

Before:

def _remove_readonly(func, path, _):
def _remove_readonly(func, path, _):
    try:
        os.chmod(path, stat.S_IWRITE)
        func(path)
    except OSError:
        pass
    func(path)

After:

def _remove_readonly(func, path, _):
    try:
        os.chmod(path, stat.S_IWRITE)
        func(path)
    except OSError:
        pass