platform2: added CPPLINT.cfg and disabled linter in minijail/

Enabled checking in cpplint for sorting headers alphabetically
as well as disabled build/include_order in platform2/*

Added CPPLINT.cfg to minijail to disable linter in that project
completely.

BUG=chromium:395296
TEST=Ran cpplint.py on platform2 manually and tried mock repo upload
     on platform2/minijail

Change-Id: I1641433be9b7bf60af0c441368845cfa042a3814
Reviewed-on: https://chromium-review.googlesource.com/209384
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/CPPLINT.cfg b/CPPLINT.cfg
new file mode 100644
index 0000000..51ff339
--- /dev/null
+++ b/CPPLINT.cfg
@@ -0,0 +1 @@
+exclude_files=.*