Simplify exception handlers

[jdufresne]

Use the "as" keyword to capture the exception in a variable instead of
sys.exc_info().

Re-raise exception with the bare "raise" syntax.

Avoid "# noqa: E722" by catching BaseException, which includes all
exceptions including SystemExit.

Pull Request check-list

Please make sure to review and check all of these items:

• Does $ tox pass with this change (including linting)?
• Does travis tests pass with this change (enable it first in your forked repo and wait for the travis build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

NOTE: these things are not required to open a PR and can be done
afterwards / while the PR is open.

[codecov-io]

Codecov Report

Merging #1319 into master will increase coverage by 0.02%.
The diff coverage is 60.00%.

@@            Coverage Diff             @@
##           master    #1319      +/-   ##
==========================================
+ Coverage   92.82%   92.84%   +0.02%     
==========================================
  Files          19       19              
  Lines        6533     6529       -4     
==========================================
- Hits         6064     6062       -2     
+ Misses        469      467       -2     

Impacted Files	Coverage Δ
redis/connection.py	82.21% <57.14%> (+0.19%)	⬆️
redis/client.py	86.27% <62.50%> (-0.01%)	⬇️

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[andymccurdy]

@jdufresne If I recall correctly, the except clauses that were empty (with the #noqa E722) for a specific reason. #328, #360 and #1128 have more details.

[jdufresne]

Yeah, that makes sense.

The old version you linked to used except Exception which does not catch SystemExit or KeyboardInterrupt. But BaseException is the base class of all exceptions and so is equivalent to a bare except: but it also signals to the reader (and tools) that all exceptions are intentionally caught and it is not simply an oversight due to an omission.

So, IMO, I this version is still preferable as it follows community conventions for catching all exceptions and avoids the need to squelch the tool. WDYT?

[andymccurdy]

Oh, gotcha. BaseException makes sense then.