sysinfo;win32: don't print the username null terminator

sysinfo_win32.cpp

@@ -63,7 +63,8 @@ cruft::util::operator<< (std::ostream &os, sysinfo const &)
 
         if (0 == GetUserNameA (&name[0], &size))
             win32::error::throw_code ();
-        name.resize (size);
+        // Remove the provided trailing null terminator
+        name.resize (size - 1);
 
         os << ", username: " << name;
     }