Fix build error with non-existent folder

Try to create the directory for output file in run_test.sh. Until now it
assumed that the caller had created the folder beforehand.

Change-Id: Icbfa09c4116bb39a54213b7e7166e73563f29ea0
diff --git a/kvm-unit-tests/run_test.sh b/kvm-unit-tests/run_test.sh
index 031cc47..b41481e 100755
--- a/kvm-unit-tests/run_test.sh
+++ b/kvm-unit-tests/run_test.sh
@@ -151,6 +151,7 @@
 		OUTPUT="$(mktemp)"
 	fi
 
+	mkdir -p "$(dirname "${OUTPUT}")"
 	"${CMD[@]}" &> "${OUTPUT}"
 	EXIT_STATUS=$?