This is a follow-up to 0627f93db6.
* gnu/packages/patches/libsantitizer-ustat-fix.patch: Rename to
gnu/packages/patches/libsanitizer-ustat-fix.patch.
* gnu/packages/llvm.scm (clang-runtime@3.7, clang-runtime@3.8,
clang-runtime@3.9)[patches]: Fix patch name.