lint: Fix long lines not being treated as actual errors.

This led to Travis CI not reporting on line-too-long errors.

tools/lint-all

@@ -166,6 +166,7 @@ def build_custom_checkers(by_lang):
                 not re.match("\[[a-z0-9_-]*\]: http.*", line) and
                     "#ignorelongline" not in line and 'migrations' not in fn):
                 print("Line too long (%s) at %s line %s: %s" % (len(line), fn, i+1, line_newline_stripped))
+                failed = True
             lastLine = line
         if lineFlag and '\n' not in lastLine:
             print("No newline at the end of file.  Fix with `sed -i '$a\\' %s`" % (fn,))