Pandoc self-contained does not properly handle links to fonts in css

[humburg]

With Pandoc 1.16.0.2 the following conversion attempt fails:

echo '<link rel="alternate stylesheet" type="text/css" href="https://netdna.bootstrapcdn.com/bootswatch/3.0.0/amelia/bootstrap.min.css" title="Amelia" media="screen"></link>' > test.md
pandoc test.md --to html --from  markdown --self-contained --output out.html

producing this error:

pandoc: Could not fetch //fonts.googleapis.com/css?family=Lobster|Cabin:400,700
InvalidUrlException "//fonts.googleapis.com/css?family=Lobster%7CCabin:400,700" "Invalid URL"

Using pandoc 1.13.2 this seems to work as expected. Related to #1477

[jgm]

For posterity, the bug was introduced by ce55834
which was intended to prevent pandoc from treating C:/ in a Windows path as a protocol.
It affects 1.16..1.16.0.2.

[humburg]

Thanks @jgm, that was very quick work.