torture: Rename RCU_BUILDONLY to TORTURE_BUILDONLY

This commit makes the torture scripts a bit more RCU-independent by
changing RCU_BUILDONLY to TORTURE_BUILDONLY.  It also removes an
unnecessary export command.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index e82f4f2..86e6ffe 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -152,7 +152,7 @@
 boot_args="`per_version_boot_params "$boot_args" $builddir/.config $seconds`"
 
 echo $QEMU $qemu_args -m 512 -kernel $builddir/arch/x86/boot/bzImage -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
-if test -n "$RCU_BUILDONLY"
+if test -n "$TORTURE_BUILDONLY"
 then
 	echo Build-only run specified, boot/test omitted.
 	exit 0