Fix undefined behavior (unaligned write) in protocol.cc

Change-Id: Ia7cf7734e534bfeef689e54c56d95d0d5cab2584

protocol.cc

diff --git a/protocol.cc b/protocol.cc
index 744dc04..c70e940 100644
--- a/protocol.cc
+++ b/protocol.cc
@@ -163,7 +163,7 @@
       len != sizeof(T)) {
     return false;
   }
-  *out_value = *reinterpret_cast<const T *>(data);
+  memcpy(out_value, data, sizeof(T));
   return true;
 }