Reduce diff to upstream re2 a bit.

third_party/re2/README.chromium

 Name: re2 - an efficient, principled regular expression library
 Short Name: re2
 URL: http://code.google.com/p/re2/
 Version: 7f91923f3ad4
 Date: 2012-06-20
 Revision: 100:7f91923f3ad4
 License: BSD 3-Clause License
 License File: LICENSE
 Security Critical: yes
 
 Description:
 RE2 is a fast, safe, thread-friendly alternative to backtracking regular
 expression engines like those used in PCRE, Perl, and Python.
 
 Local Modifications (to be applied in this order):
 - Remove valgrind specific code that exists in chromium already
   (patches/remove-valgrind-code.patch)
 - Support for Windows (patches/re2-msvc9-chrome.patch)
 - Support Android (patches/re2-android.patch)
 - Remove static initializers (patches/remove-static-initializers.patch)
 - Rename POSIX configuration (patches/rename-posix-option.patch)
 - Support libcxx (patches/re2-libcxx.patch)
   https://code.google.com/p/re2/issues/detail?id=76
 - Memory optimization for filtered trees
   (patches/re2-memory-optimization.patch)
 - Prevent unwanted reports from MemorySanitizer. Note: there's an upstream fix
   for this (https://code.google.com/p/re2/issues/detail?id=77) which is rendered
   ineffective by patches/remove-valgrind-code.patch
   (patches/re2-msan.patch)
-- Remove comparisons of this with NULL (patches/this-null.patch), merges
-  upstream b92ce81f1e25
+- Remove comparisons of this with NULL, merges upstream b92ce81f1e25
 - Let COMPILE_ASSERT use static_assert if available, merges upstream
   2225f94df8ec