Fix an ImportError w/Blosc on Android

[danieldjewell]

Android does not have a functioning semaphore system (actually it's
bionic-C that doesn't...). When trying to import numcodecs.blosc on
Android, an ImportError exception was thrown - which was unhandled.

[Description of PR]

TODO:

• Unit tests and/or doctests in docstrings
• tox -e py39 passes locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• tox -e docs passes locally
• GitHub Actions CI passes
• Test coverage to 100% (Coveralls passes)

[danieldjewell]

Just to add: I'm aware of #274 and the discussion in #283. Since that is still a WIP, it seemed like this small fix in the interim would be a good idea.

[joshmoore]

The additional catch makes sense to me. Ignoring the state of the actions since the failures are unrelated. 👍

Leaving this open briefly for any last minute comments, but then happy to get it out as a quick release.

[joshmoore]

Released as 0.8.1