Fix wpull.scraper.html_test.TestHTMLScraper

[ivan]

probably broken by my parser changes:

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FAIL: test_html_scraper_links (wpull.scraper.html_test.TestHTMLScraper)
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Traceback (most recent call last):
  File "/home/grab/wpull/thematrix/wpull/scraper/html_test.py", line 84, in test_html_scraper_links
    inline_urls
AssertionError: Items in the first set but not the second:
'http://example.com/frame_src.html'
-------------------- >> begin captured logging << --------------------
wpull.document.util: DEBUG: Got encoding: utf-8
wpull.scraper.util: WARNING: Unable to parse URL ‘http://example.invalid](http://example.invalid’: Invalid IPv6 URL.
--------------------- >> end captured logging << ---------------------

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FAIL: test_html_scraper_links_base_href (wpull.scraper.html_test.TestHTMLScraper)
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Traceback (most recent call last):
  File "/home/grab/wpull/thematrix/wpull/scraper/html_test.py", line 279, in test_html_scraper_links_base_href
    inline_urls
AssertionError: {'http://example.com/a/dir/image1.png', 'http://example.com/dir/image4.png', 'http://www.example.com/stylesheet2.css', 'http://example.net/image3.png', 'http://example.com/dir/image2.png', 'http://example.com/a/stylesheet3.css', 'http://cdn.example.com/stylesheet1.css'} != frozenset({'http://example.net/image3.png', 'http://example.com/dir/image4.png', 'http://example.com/dir/image1.png', 'http://example.com/dir/image2.png'})
-------------------- >> begin captured logging << --------------------
wpull.document.util: DEBUG: Got encoding: utf-8
--------------------- >> end captured logging << ---------------------