Add missing cast whose absence caused us to use 32-bit arithmetic on ia32 during testing (but not in the Apache module).
Add missing cast whose absence caused us to use 32-bit arithmetic on ia32 during
testing (but not in the Apache module).

crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp