chrono: correct the units for the epoch bias
chrono: correct the units for the epoch bias

As pointed out by Howard, this is actually 134774 days (* 24 * 3600),
and therefore seconds, not 100ns units.  Adjust the units to reflect
reality.

git-svn-id: 756ef344af921d95d562d9e9f9389127a89a6314@290824 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx