Comment # 1 on bug 1219405 from Shung-Hsi Yu

I don't use c-index-test per se. This is just something I discovered while
trying looking at libclang.so.

Seems like we'd need tools that depends on older version of llvm should link
with /lib64/libclang.so.$ver from the corresponding llvm$ver-libclang package
rather than the libclang package?