Fix minor initialization bug in Registers_x86_64.

According to kledzik, this constructor isn't live code, so no functionality
change.



git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@196550 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/src/Unwind/Registers.hpp b/src/Unwind/Registers.hpp
index a0050dd..96eefd5 100644
--- a/src/Unwind/Registers.hpp
+++ b/src/Unwind/Registers.hpp
@@ -1066,7 +1066,7 @@
 
 inline Registers_arm64::Registers_arm64() {
   bzero(&_registers, sizeof(_registers));
-  bzero(&_registers, sizeof(_vectorHalfRegisters));
+  bzero(&_vectorHalfRegisters, sizeof(_vectorHalfRegisters));
 }
 
 inline bool Registers_arm64::validRegister(int regNum) const {