check-code: remove redundant import style check

We have a dedicated tool that checks for import conventions. Remove
a redundant and less powerful check.

contrib/check-code.py

@@ -218,9 +218,6 b' pypats = ['
      "tuple parameter unpacking not available in Python 3+"),
     (r'lambda\s*\(.*,.*\)',
      "tuple parameter unpacking not available in Python 3+"),
-    (r'import (.+,[^.]+\.[^.]+|[^.]+\.[^.]+,)',
-     '2to3 can\'t always rewrite "import qux, foo.bar", '
-     'use "import foo.bar" on its own line instead.'),
     (r'(?<!def)\s+(cmp)\(', "cmp is not available in Python 3+"),
     (r'\breduce\s*\(.*', "reduce is not available in Python 3+"),
     (r'dict\(.*=', 'dict() is different in Py2 and 3 and is slower than {}',