Extra “http://doi.org/” with chicago-author-date.csl

[njbart]

Regression, possibly related to #163:

pandoc -F pandoc-citeproc << EOT

---
references:
- id: 1
  type: article-journal
  DOI: 10.1234/1234567890
...

@1
EOT

Actual:

<p><span class="citation">(n.d.)</span></p>
<div id="references" class="references">
<div id="ref-1">
<p>n.d. doi:<a href="http://doi.org/10.1234/1234567890" class="uri">http://doi.org/10.1234/1234567890</a>.</p>
</div>
</div>

Expected:

<p><span class="citation">(n.d.)</span></p>
<div id="references" class="references">
<div id="ref-1">
<p>n.d. doi:<a href="http://doi.org/10.1234/1234567890" class="uri">10.1234/1234567890</a>.</p>
</div>
</div>

Cf. the example in CMoS, 16e, 14.18: “Novak, William J. “The Myth of the ‘Weak’ American State.” American Historical Review 113 (June 2008): 752–72. doi:10.1086/ahr.113.3.752.”

Note that in Zotero/LO this is (still) rendered as expected, and also that the issue is not limited to chicago-author-date.csl but affects many styles.