panick processing Python .pyc file not slated for inclusion

Nobody has claimed this yet.

I have some junk in my site-packages, and PyOxidizer is choking when it encounters them, when it should report and move on as these files are irrelevant to the rule.
(adding `excludes: ["cproton"]` also didnt help)

```rust
processing packaging rule: PackageRoot(PackagingPackageRoot { path: "/usr/lib64/python3.7", packages: ["distutils", "distutils.tests", "idlelib", "idlelib.idle_test"], optimize_level: 0, excludes: [], include_source: true, install_location: Embedded })
thread 'main' panicked at 'encountered .pyc file with invalid path: cproton.pyc', /home/jayvdb/.cargo/registry/src/github.com-1ecc6299db9ec823/pyoxidizer-0.4.0/src/pyrepackager/fsscan.rs:260:21
stack backtrace:
0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
1: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:71
at src/libstd/sys_common/backtrace.rs:59
2: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:197
3: std::panicking::default_hook
at src/libstd/panicking.rs:211
4: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:474
5: std::panicking::continue_panic_fmt
at src/libstd/panicking.rs:381
6: std::panicking::begin_panic_fmt
at src/libstd/panicking.rs:336
7: ::next
8: pyoxidizer::pyrepackager::packaging_rule::resolve_python_packaging
9: pyoxidizer::pyrepackager::repackage::resolve_python_resources
10: pyoxidizer::pyrepackager::repackage::process_config
11: pyoxidizer::projectmgmt::build_pyoxidizer_artifacts
12: pyoxidizer::projectmgmt::build_project
13: pyoxidizer::cli::run_cli
14: pyoxidizer::main
15: std::rt::lang_start::{{closure}}
16: std::panicking::try::do_call
at src/libstd/rt.rs:49
at src/libstd/panicking.rs:293
17: __rust_maybe_catch_panic
at src/libpanic_unwind/lib.rs:87
18: std::rt::lang_start_internal
at src/libstd/panicking.rs:272
at src/libstd/panic.rs:388
at src/libstd/rt.rs:48
19: main
20: __libc_start_main
21: _start
at ../sysdeps/x86_64/start.S:120
```

Start at src/pyrepackager/fsscan.rs:260 in PythonResourceIterator::next, then follow the packaging path through resolve_python_packaging. Reproduce the PackageRoot scan containing cproton.pyc and verify that an invalid, excluded .pyc is reported or skipped without panicking.

Written by the indexing model from the issue text.