[#9127] http auth session wrapper py3 fix

[tardyp]

fix for buildbot/buildbot#3162

[Codecov]

Codecov Report

Merging #773 into trunk will decrease coverage by 2.33%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##            trunk     #773      +/-   ##
==========================================
- Coverage   91.58%   89.25%   -2.34%     
==========================================
  Files         841      841              
  Lines      146777   146788      +11     
  Branches    12860    12860              
==========================================
- Hits       134432   131017    -3415     
- Misses      10100    13353    +3253     
- Partials     2245     2418     +173

[tardyp]

@rodrigc fyi a py3 fix. I am not sure why the buildbot tests are not running.

[rodrigc]

Sometimes these nativeString and networkString functions are a necessary evil, but can we fix this somehow without using them?

Something like:

    l.append(k + b"=" + quoteString(v))