xfstests: generic/273: do not use /proc/cpuinfo

The content of /proc/cpuinfo file is platform-dependent.
So we can not use it reliably to check a number of available cpus.
It would be better to use sysfs interface, as _no_of_online_cpus() does.

Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>

tests/generic/273

@@ -47,7 +47,7 @@ count=2
 
 _threads_set()
 {
-	_cpu_num=`cat /proc/cpuinfo | grep "processor" | wc -l`
+	_cpu_num=`_no_of_online_cpus`
 	threads=$(($_cpu_num * 50))
 	if [ $threads -gt 200 ]
 	then