libhwbinder: support '0' fd for binder

If someone closes stdin, the 0 FD may be reused when the /dev/hwbinder
fd is opened. In this case, don't consider it an error (though other
code in the process should be careful to avoid using stdin).

Bug: 175342959
Test: boot
Change-Id: Ic19db0131e68631ceb9970ff13989e4907ba73ce
1 file changed