Fixed typo in run_tests.sh file

Change-Id: I3d81c3de35ec654c5c2e1520b7752dd36523096f
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 78dd2c1..868a639 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -111,7 +111,7 @@
 }
 
 salt_run() {
-    [ -e ${VEN_DIR}/bin/activate ] && source ${VENV_DIR}/bin/activate
+    [ -e ${VENV_DIR}/bin/activate ] && source ${VENV_DIR}/bin/activate
     salt-call ${SALT_OPTS} $*
 }