Add lint check for integer constants (#775)

script/ci-custom.py

@@ -5,6 +5,7 @@ import codecs
 import collections
 import fnmatch
 import os.path
+import re
 import subprocess
 import sys
 import re
@@ -262,7 +263,6 @@ def lint_constants_usage():
         errors.append("Constant {} is defined in {} files. Please move all definitions of the "
                       "constant to const.py (Uses: {})"
                       "".format(highlight(constant), len(uses), ', '.join(uses)))
-    return errors
 
 
 def relative_cpp_search_text(fname, content):