Simplify ticks, as the value is a constant

See for example in the Musl libc source code https://git.musl-libc.org/cgit/musl/tree/src/conf/sysconf.c#n29

This removes the cgo dependency for the system package.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

libcontainer/system/sysconfig.go

@@ -1,12 +0,0 @@
-// +build cgo,linux
-
-package system
-
-/*
-#include <unistd.h>
-*/
-import "C"
-
-func GetClockTicks() int {
-	return int(C.sysconf(C._SC_CLK_TCK))
-}

libcontainer/system/sysconfig_notcgo.go

@@ -1,15 +0,0 @@
-// +build !cgo windows
-
-package system
-
-func GetClockTicks() int {
-	// TODO figure out a better alternative for platforms where we're missing cgo
-	//
-	// TODO Windows. This could be implemented using Win32 QueryPerformanceFrequency().
-	// https://msdn.microsoft.com/en-us/library/windows/desktop/ms644905(v=vs.85).aspx
-	//
-	// An example of its usage can be found here.
-	// https://msdn.microsoft.com/en-us/library/windows/desktop/dn553408(v=vs.85).aspx
-
-	return 100
-}