Alias sys_setdomainname to sys_sethostname

Since parsers for setdomainname and sethostname syscalls are identical,
replace sys_setdomainname with an alias to sys_sethostname.

* linux/dummy.h (sys_setdomainname): Alias to sys_sethostname.
* linux/syscall.h (sys_setdomainname): Remove.
* process.c (sys_setdomainname): Remove.
3 files changed