llvm-cov: Fixed some bugs related to file checksum.

Added call to update CfgChecksum. Made FileChecksum a vector, separate
for each source file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195309 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed