Add monkey patching for botocore.httpsession

[kolanos]

Closes #319

[codecov]

Codecov Report

Merging #321 into master will decrease coverage by 0.52%.
The diff coverage is 69.81%.

@@            Coverage Diff             @@
##           master     #321      +/-   ##
==========================================
- Coverage   83.47%   82.95%   -0.53%     
==========================================
  Files          36       36              
  Lines        1283     1320      +37     
==========================================
+ Hits         1071     1095      +24     
- Misses        212      225      +13

Impacted Files	Coverage Δ
iopipe/contrib/trace/auto_http.py	76.1% <69.81%> (-5.48%)	⬇️

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[mrickard]

It looks like this one's consistently failing on the python 2.7 build. I'm not quite sure where that's failing, exactly...but this seems like something we should correct before we remove support for it.

[kolanos]

@mrickard The python2.7 issue is fixed. The code coverage will be tricky as I'd need to monkey patch a monkey patch to properly mock that, will require further investigation as to the best method to do that. Only a minor drop in code coverage for now.

[mrickard]

👍 @kolanos That's definitely tricky. Very meta. Thanks!