CppLint changes for VSCode cpplint plugin

This patch makes some changes to the cpplint.py script for integration
with the VSCode cpplint plugin, available here:

https://marketplace.visualstudio.com/items?itemName=mine.cpplint

Specifically, the "--repository" and "--headers" options currently cause
our version of cpplint to crash, when we should at worst ignore them. A
minor messaging tweak outputting the contents of the GetoptError, to
make debugging input argument bugs easier, is included

Change-Id: Id78616f5e2fdecb7da650042f0658623477ef9cb
Reviewed-on: https://chromium-review.googlesource.com/c/1481938Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Jordan Bayles <jophba@chromium.org>

cpplint.py

@@ -6004,14 +6004,16 @@ def ParseArguments(args):
   """
   try:
     (opts, filenames) = getopt.getopt(args, '', ['help', 'output=', 'verbose=',
+                                                 'headers=', # We understand but ignore headers.
                                                  'counting=',
                                                  'filter=',
                                                  'root=',
                                                  'linelength=',
                                                  'extensions=',
-                                                 'project_root='])
-  except getopt.GetoptError:
-    PrintUsage('Invalid arguments.')
+                                                 'project_root=',
+                                                 'repository='])
+  except getopt.GetoptError as e:
+    PrintUsage('Invalid arguments: {}'.format(e))
 
   verbosity = _VerboseLevel()
   output_format = _OutputFormat()
@@ -6038,7 +6040,7 @@ def ParseArguments(args):
     elif opt == '--root':
       global _root
       _root = val
-    elif opt == '--project_root':
+    elif opt == '--project_root' or opt == "--repository":
       global _project_root
       _project_root = val
       if not os.path.isabs(_project_root):