TEST: Use correct variable when checking for DH functionality

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/tests/keyctl/dh_compute/noargs/runtest.sh b/tests/keyctl/dh_compute/noargs/runtest.sh
index 3795f4b..e761f6b 100644
--- a/tests/keyctl/dh_compute/noargs/runtest.sh
+++ b/tests/keyctl/dh_compute/noargs/runtest.sh
@@ -6,7 +6,7 @@
 
 # ---- do the actual testing ----
 
-if [ $have_key_invalidate = 0 ]
+if [ $have_dh_compute = 0 ]
 then
     toolbox_skip_test $TEST "SKIPPING DUE TO LACK OF DIFFIE-HELLMAN"
     exit 0
diff --git a/tests/keyctl/dh_compute/valid/runtest.sh b/tests/keyctl/dh_compute/valid/runtest.sh
index f21cb11..40ec387 100644
--- a/tests/keyctl/dh_compute/valid/runtest.sh
+++ b/tests/keyctl/dh_compute/valid/runtest.sh
@@ -6,7 +6,7 @@
 
 # ---- do the actual testing ----
 
-if [ $have_key_invalidate = 0 ]
+if [ $have_dh_compute = 0 ]
 then
     toolbox_skip_test $TEST "SKIPPING DUE TO LACK OF DIFFIE-HELLMAN"
     exit 0