Remove obsolete version checks

[elacuesta]

Removing more version checks after bumping minimum package versions in #3892 (Twisted, pyOpenSSL)

I must admit, in the last commit I might have got too excited about indentation and PEP8 (but not the 79-char limit), so feel free to disregard that one (hopefully you won't 🤞 😄)

[codecov]

Codecov Report

Merging #3950 into master will increase coverage by 0.19%.
The diff coverage is 90.69%.

@@            Coverage Diff             @@
##           master    #3950      +/-   ##
==========================================
+ Coverage   85.11%   85.31%   +0.19%     
==========================================
  Files         167      167              
  Lines        9744     9709      -35     
  Branches     1457     1453       -4     
==========================================
- Hits         8294     8283      -11     
+ Misses       1188     1168      -20     
+ Partials      262      258       -4

Impacted Files	Coverage Δ
scrapy/core/downloader/tls.py	86.04% <81.25%> (+10.12%)	⬆️
scrapy/core/downloader/contextfactory.py	96.15% <96%> (+21.15%)	⬆️
scrapy/core/downloader/handlers/http11.py	92.91% <96.55%> (+2.98%)	⬆️

[codecov]

Codecov Report

Merging #3950 into master will increase coverage by 0.19%.
The diff coverage is 90.69%.

@@            Coverage Diff             @@
##           master    #3950      +/-   ##
==========================================
+ Coverage   85.11%   85.31%   +0.19%     
==========================================
  Files         167      167              
  Lines        9744     9709      -35     
  Branches     1457     1453       -4     
==========================================
- Hits         8294     8283      -11     
+ Misses       1188     1168      -20     
+ Partials      262      258       -4

Impacted Files	Coverage Δ
scrapy/core/downloader/tls.py	86.04% <81.25%> (+10.12%)	⬆️
scrapy/core/downloader/contextfactory.py	96.15% <96%> (+21.15%)	⬆️
scrapy/core/downloader/handlers/http11.py	92.91% <96.55%> (+2.98%)	⬆️

[Gallaecio]

I really prefer style changes only in the affected lines when a change is not specifically about style changes, otherwise reviewing can become a bit more annoying to me. But your changes, @elacuesta, are always worth the trouble :)

[elacuesta]

I know, I know, sorry about that 😅
In my defense, I suspected there should be a way to view only a subset of the changes, and indeed it seems like Githhub does allow to select a specific range of commits to review: the first 8 commits can be seen at https://github.com/scrapy/scrapy/pull/3950/files/d5dcc5eaef80ef383dff90f19349c0e06f1836a6. The version-specific changes are more obvious that way in the downloader handler file.

[kmike]

Thanks @elacuesta!