Fixed typo in run_tests.sh file

Change-Id: I6c907e243a21659044324c1a2bb095211942c1b7
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index a4cac88..db89554 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -113,7 +113,7 @@
 }
 
 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} $*
 }