When catching and converting exceptions, handle connection errors first

[sjaensch]

Some HTTP libraries (in my case, aiohttp) have exception hierarchies that themselves use multiple inheritance to make sure the specific exceptions they throw also inherit from a generic timeout exception (here: asyncio.TimeoutError). Additionally, they sometimes have bugs where they don't raise the exact exception type they should be raising in specific circumstances: see aiohttp/client.py.

What I'm proposing here is to just switch around two catch statements: in almost all cases, connection errors are either completely separate exceptions from timeout errors, or they are the more specific exception. So catching connection errors first is the safer thing to do.

This fixes a recent build failure for bravado-asyncio, where new versions of aiohttp again changed things with connection errors. We already have code to disable bravado connection error integration tests on Windows since this was an issue on that platform for quite some time already.

I've verified that this change not only fixes the recent build failure, but also makes the tests work properly on Windows.

[coveralls]

Coverage remained the same at 96.344% when pulling fb8b650 on connection-errors-take-precedence into a7858f6 on master.

[sjaensch]

@analogue could you please take a look when you have time? This not only fixes an issue with exception handling when used with bravado-asyncio, but also fixes bravado's build.

[analogue]

🚢