Default syntax error offset to zero pyflakes (#332)

* Default to zero

* Default to zero

Author: gatesn

pyls/plugins/pyflakes_lint.py

@@ -35,6 +35,10 @@ def unexpectedError(self, filename, msg):  # pragma: no cover
         pass
 
     def syntaxError(self, _filename, msg, lineno, offset, text):
+        # We've seen that lineno and offset can sometimes be None
+        lineno = lineno or 1
+        offset = offset or 0
+
         err_range = {
             'start': {'line': lineno - 1, 'character': offset},
             'end': {'line': lineno - 1, 'character': offset + len(text)},