qemu-check.exp: Fix uninitialized variables

Fix uninitialized variables in procedure 'check_test_result'.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
diff --git a/qemu-check.exp b/qemu-check.exp
index c7e5c8a..fdba942 100644
--- a/qemu-check.exp
+++ b/qemu-check.exp
@@ -56,6 +56,8 @@
 
 proc check_test_result arg {
 	set casenum "none"
+	set star 0
+	set ncases 0
 	expect {
 		# Exit with error status as soon as a test fails
 		-re {  ([^ ]+) FAIL} {