Fixes nested reasons being overwritten by outer spec's reason #171.

[Sardtok]

This should fix #171, where a reason set on an outer spec overwrites the inner problem's reason.

[codecov-commenter]

Codecov Report

Merging #267 (ae28029) into master (8a3284f) will not change coverage.
Report is 9 commits behind head on master.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #267   +/-   ##
=======================================
  Coverage   88.01%   88.01%           
=======================================
  Files          16       16           
  Lines        2052     2052           
  Branches      183      183           
=======================================
  Hits         1806     1806           
  Misses         63       63           
  Partials      183      183           

Files Changed	Coverage Δ
src/spec_tools/core.cljc	94.42% <100.00%> (ø)

... and 1 file with indirect coverage changes

[Sardtok]

@ikitommi Have you had a look at this?

[Sardtok]

Has anyone had an opportunity to look at the PR? If there are any reasons, like lack of regression tests, that block merging it, I'd be happy to update it.

[ikitommi]

Thanks for the fix, I'll merge and add a test.