Fixed typo in run_tests.sh file

Change-Id: I796f1554fd09bccbbcdfb216a74421c922a82d89
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 29fb975..4ee4e0f 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -124,7 +124,7 @@
 }
 
 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} $*
 }