[analyzer] dump_ast_matchers.py: fix replacement regexps

Patch by Alex Sidorin!

Differential Revision: http://reviews.llvm.org/D17376


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261219 91177308-0d34-0410-b5e6-96231b3b80d8