Removed CMake cache upgrade code from 2011

Summary:
This code was added in r141266 to make a breaking change to CMake, but
still be compatible with existing cache files.  The cache files from
2011 are irrelevant today in 2019.

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60711

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358482 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed