Simplify generation of sec-websocket-key

The result of `g()` is a random number, therefore it's not necessary
to care about endianness in this case.

Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>

include/boost/beast/websocket/detail/hybi13.ipp

@@ -27,18 +27,12 @@ void
 make_sec_ws_key(sec_ws_key_type& key)
 {
     auto g = make_prng(true);
-    char a[16];
-    for(int i = 0; i < 16; i += 4)
-    {
-        auto const v = g();
-        a[i  ] =  v        & 0xff;
-        a[i+1] = (v >>  8) & 0xff;
-        a[i+2] = (v >> 16) & 0xff;
-        a[i+3] = (v >> 24) & 0xff;
-    }
+    std::uint32_t a[4];
+    for (auto& v : a)
+        v = g();
     key.resize(key.max_size());
     key.resize(beast::detail::base64::encode(
-        key.data(), &a[0], 16));
+        key.data(), &a[0], sizeof(a)));
 }
 
 void