Do not read syscall no in get_scno_on_sysexit
Do not read syscall no in get_scno_on_sysexit

* syscall.c (get_scno_on_sysexit): Remove scno retrieval code, since
we don't save it anyway. This is the first real logic change
which should make strace faster: for example, on x64 ORIG_EAX
is no longer read in each syscall exit.

Signed-off-by: Denys Vlasenko <50fbbd36fe0f9c8261d4a3c762c8c29ffb35e48f@redhat.com>

gcode-mirror/strace-plus,lkundrak/strace,pgbovine/strace-plus,CyanogenMod/android_external_strace,Andrey9kin/revisor,TeamExodus/external_strace,vrastogi/strace,bnoordhuis/strace,lizh06/strace-plus,Andrey9kin/revisor,Distrotech/strace,geekboxzone/lollipop_external_strace,bigzz/strace_android,timmattison/strace-arm,lizh06/strace-plus,cuviper/strace,kapdop/android_external_strace,android-ia/platform_external_strace,jamel/strace-plus,kapdop/android_external_strace,Infinitive-OS/platform_external_strace,MonkeyZZZZ/platform_external_strace,kapdop/android_external_strace,Yu-AndroidM/android_external_strace,geekboxzone/lollipop_external_strace,lizh06/strace-plus,CyanogenMod/android_external_strace,TeamExodus/external_strace,geofft/strace,vrastogi/strace,CyanogenMod/android_external_strace,Distrotech/strace,YUPlayGodDev/platform_external_strace,Saruta/strace,vrastogi/strace,vrastogi/strace,geekboxzone/lollipop_external_strace,pgbovine/strace-plus,kapdop/android_external_strace,Infinitive-OS/platform_external_strace,xin3liang/platform_external_strace,timmattison/strace-arm,android-ia/platform_external_strace,pombredanne/strace,geekboxzone/mmallow_external_strace,pombredanne/strace,AOSP-YU/platform_external_strace,Saruta/strace,lkundrak/strace,geekboxzone/lollipop_external_strace,Yu-AndroidM/android_external_strace,geekboxzone/mmallow_external_strace,Distrotech/strace,bigzz/strace_android,lkundrak/strace,DirtyUnicorns/android_external_strace,Yu-AndroidM/android_external_strace,lizh06/strace-plus,geofft/strace,MonkeyZZZZ/platform_external_strace,geofft/strace,pgbovine/strace-plus,Distrotech/strace,pombredanne/strace,AOSP-YU/platform_external_strace,Infinitive-OS/platform_external_strace,xin3liang/platform_external_strace,android-ia/platform_external_strace,cuviper/strace,TeamExodus/external_strace,YUPlayGodDev/platform_external_strace,android-ia/platform_external_strace,geekboxzone/mmallow_external_strace,android-ia/platform_external_strace,jamel/strace-plus,AOSP-YU/platform_external_strace,Saruta/strace,geofft/strace,timmattison/strace-arm,gcode-mirror/strace-plus,Infinitive-OS/platform_external_strace,CyanogenMod/android_external_strace,TeamExodus/external_strace,Distrotech/strace,AOSP-YU/platform_external_strace,bigzz/strace_android,xin3liang/platform_external_strace,geekboxzone/mmallow_external_strace,MonkeyZZZZ/platform_external_strace,YUPlayGodDev/platform_external_strace,lkundrak/strace,TeamExodus/external_strace,pombredanne/strace,gcode-mirror/strace-plus,AOSP-YU/platform_external_strace,gcode-mirror/strace-plus,DirtyUnicorns/android_external_strace,CyanogenMod/android_external_strace,Andrey9kin/revisor,jamel/strace-plus,bigzz/strace_android,bnoordhuis/strace,bnoordhuis/strace,MonkeyZZZZ/platform_external_strace,Saruta/strace,jamel/strace-plus,geekboxzone/lollipop_external_strace,cuviper/strace,lizh06/strace-plus,geofft/strace,YUPlayGodDev/platform_external_strace,gcode-mirror/strace-plus,cuviper/strace,pgbovine/strace-plus,vrastogi/strace,bnoordhuis/strace,kapdop/android_external_strace,Infinitive-OS/platform_external_strace,pgbovine/strace-plus,Andrey9kin/revisor,jamel/strace-plus,Yu-AndroidM/android_external_strace,DirtyUnicorns/android_external_strace,DirtyUnicorns/android_external_strace,xin3liang/platform_external_strace,Yu-AndroidM/android_external_strace,cuviper/strace,bigzz/strace_android,DirtyUnicorns/android_external_strace,Saruta/strace,YUPlayGodDev/platform_external_strace,geekboxzone/mmallow_external_strace,MonkeyZZZZ/platform_external_strace