net.c: remove unused HAVE_SIN6_SCOPE_ID_LINUX-based code
net.c: remove unused HAVE_SIN6_SCOPE_ID_LINUX-based code

The AC_SIN6_SCOPE_ID autoconf macro that was able to define
HAVE_SIN6_SCOPE_ID_LINUX was removed by commit v4.4-98-g64f793a.

* net.c [HAVE_SIN6_SCOPE_ID_LINUX]: Remove.

Yu-AndroidM/android_external_strace,YUPlayGodDev/platform_external_strace,geofft/strace,YUPlayGodDev/platform_external_strace,kapdop/android_external_strace,cuviper/strace,bigzz/strace_android,Yu-AndroidM/android_external_strace,Distrotech/strace,Saruta/strace,Infinitive-OS/platform_external_strace,Saruta/strace,geekboxzone/mmallow_external_strace,TeamExodus/external_strace,AOSP-YU/platform_external_strace,kapdop/android_external_strace,vrastogi/strace,Infinitive-OS/platform_external_strace,YUPlayGodDev/platform_external_strace,Saruta/strace,Yu-AndroidM/android_external_strace,bigzz/strace_android,MonkeyZZZZ/platform_external_strace,Infinitive-OS/platform_external_strace,TeamExodus/external_strace,geekboxzone/mmallow_external_strace,vrastogi/strace,MonkeyZZZZ/platform_external_strace,bnoordhuis/strace,AOSP-YU/platform_external_strace,bigzz/strace_android,vrastogi/strace,MonkeyZZZZ/platform_external_strace,bigzz/strace_android,bigzz/strace_android,vrastogi/strace,geofft/strace,MonkeyZZZZ/platform_external_strace,Distrotech/strace,Distrotech/strace,Saruta/strace,Yu-AndroidM/android_external_strace,geekboxzone/mmallow_external_strace,geofft/strace,Infinitive-OS/platform_external_strace,kapdop/android_external_strace,geofft/strace,bnoordhuis/strace,cuviper/strace,geekboxzone/mmallow_external_strace,MonkeyZZZZ/platform_external_strace,YUPlayGodDev/platform_external_strace,bnoordhuis/strace,cuviper/strace,Yu-AndroidM/android_external_strace,cuviper/strace,TeamExodus/external_strace,AOSP-YU/platform_external_strace,Infinitive-OS/platform_external_strace,Distrotech/strace,Distrotech/strace,TeamExodus/external_strace,kapdop/android_external_strace,kapdop/android_external_strace,AOSP-YU/platform_external_strace,cuviper/strace,TeamExodus/external_strace,bnoordhuis/strace,geekboxzone/mmallow_external_strace,AOSP-YU/platform_external_strace,YUPlayGodDev/platform_external_strace,Saruta/strace,vrastogi/strace,geofft/strace