torture: Enable versions without CFcommon to function correctly

The CFcommon file must now be present, which makes using the current
scripts against old kernel versions cumbersome.  This commit therefore
makes the CFcommon file be optional, so that old kernel versions can be
used with current torture scripts.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh

@@ -42,6 +42,7 @@ grace=120
 
 T=/tmp/kvm-test-1-run.sh.$$
 trap 'rm -rf $T' 0
+touch $T
 
 . $KVM/bin/functions.sh
 . $KVPATH/ver_functions.sh