dev-python/lxml: disable broken test-case, EAPI upgrade

There is a test-case not working because of issues in
libxml2. The patch disables the one broken test-case
until upstream can fix it.

Upstream bug: https://bugs.launchpad.net/lxml/+bug/1608479

Gentoo-Bug: https://bugs.gentoo.org/show_bug.cgi?id=592860

Package-Manager: portage-2.3.0
Closes: https://github.com/gentoo/gentoo/pull/2539

Signed-off-by: David Seifert <soap@gentoo.org>

dev-python/lxml/files/lxml-3.6.4-fix-test_xmlschema.patch

@@ -0,0 +1,36 @@
+diff --git a/src/lxml/tests/test_xmlschema.py b/src/lxml/tests/test_xmlschema.py
+index 26d8432..b41c097 100644
+--- a/src/lxml/tests/test_xmlschema.py
++++ b/src/lxml/tests/test_xmlschema.py
+@@ -168,31 +168,6 @@ class ETreeXMLSchemaTestCase(HelperTestCase):
+         self.assertEqual('ho', root[2].get('hardy'))
+         self.assertEqual('hey', root[3].get('hardy'))
+ 
+-    def test_xmlschema_parse_fixed_attributes(self):
+-        # does not work as of libxml2 2.7.3
+-        schema = self.parse('''
+-<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+-  <xsd:element name="a" type="AType"/>
+-  <xsd:complexType name="AType">
+-    <xsd:sequence minOccurs="3" maxOccurs="3">
+-      <xsd:element name="b" type="BType" />
+-    </xsd:sequence>
+-  </xsd:complexType>
+-  <xsd:complexType name="BType">
+-    <xsd:attribute name="hardy" type="xsd:string" fixed="hey" />
+-  </xsd:complexType>
+-</xsd:schema>
+-''')
+-        schema = etree.XMLSchema(schema)
+-        parser = etree.XMLParser(schema=schema, attribute_defaults=True)
+-
+-        tree_valid = self.parse('<a><b/><b hardy="hey"/><b/></a>',
+-                                parser=parser)
+-        root = tree_valid.getroot()
+-        self.assertEqual('hey', root[0].get('hardy'))
+-        self.assertEqual('hey', root[1].get('hardy'))
+-        self.assertEqual('hey', root[2].get('hardy'))
+-
+     def test_xmlschema_stringio(self):
+         schema_file = BytesIO('''
+ <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">