Make naming in Host.h in line with coding standards.

Based on post-commit review comments by Chandler Carruth on
https://reviews.llvm.org/D31236. Thanks!

llvm-svn: 299211
diff --git a/llvm/lib/Support/Chrono.cpp b/llvm/lib/Support/Chrono.cpp
index ca748f5..daccaf1 100644
--- a/llvm/lib/Support/Chrono.cpp
+++ b/llvm/lib/Support/Chrono.cpp
@@ -16,12 +16,12 @@
 
 using namespace sys;
 
-const char detail::unit<std::ratio<3600>>::value[] = "h";
-const char detail::unit<std::ratio<60>>::value[] = "m";
-const char detail::unit<std::ratio<1>>::value[] = "s";
-const char detail::unit<std::milli>::value[] = "ms";
-const char detail::unit<std::micro>::value[] = "us";
-const char detail::unit<std::nano>::value[] = "ns";
+const char llvm::detail::unit<std::ratio<3600>>::value[] = "h";
+const char llvm::detail::unit<std::ratio<60>>::value[] = "m";
+const char llvm::detail::unit<std::ratio<1>>::value[] = "s";
+const char llvm::detail::unit<std::milli>::value[] = "ms";
+const char llvm::detail::unit<std::micro>::value[] = "us";
+const char llvm::detail::unit<std::nano>::value[] = "ns";
 
 static inline struct tm getStructTM(TimePoint<> TP) {
   struct tm Storage;