Invoke setup_venv.sh using bash

Change-Id: I1c4e7da18ae54fe4dd5eab58a1c06d263837cba6
diff --git a/seba-in-a-box/Makefile b/seba-in-a-box/Makefile
index c8117e2..c665aaf 100644
--- a/seba-in-a-box/Makefile
+++ b/seba-in-a-box/Makefile
@@ -168,7 +168,7 @@
 
 $(M)/qatests: $(M)/siab $(M)/qatests-prereqs $(WORKSPACE)/cord/test/cord-tester
 	cd $(WORKSPACE)/cord/test/cord-tester/src/test/cord-api/ && \
-		./setup_venv.sh && \
+		bash ./setup_venv.sh && \
 		source ./venv-cord-tester/bin/activate && \
 		cd Tests/WorkflowValidations/ && \
 		pybot -e notready SIAB.robot