Fix MIME type check for example OFX importer.

Ensure that we will accept the non-strict type we added,
and don't try to match a tuple against a string.

examples/importers/ofx.py

@@ -66,7 +66,7 @@ def __init__(self, acctid_regexp, account, basename=None,
 
     def identify(self, filepath):
         # Match for a compatible MIME type.
-        if mimetypes.guess_type(filepath) not in {'application/x-ofx',
+        if mimetypes.guess_type(filepath, strict=False)[0] not in {'application/x-ofx',
                                                   'application/vnd.intu.qbo',
                                                   'application/vnd.intu.qfx'}:
             return False