Fix typo for run_tests.sh -S option

This patch fixes a typo of getopt's arguments. If the second 's' option letter
is not 'S', -S option is not recognized.

Fix bug 1161921

Change-Id: I0b5a372e7257b9319b350131303c1a9f51b57eb5
diff --git a/run_tests.sh b/run_tests.sh
index 3f394e3..25b9729 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -33,7 +33,7 @@
 config_file=""
 update=0
 
-if ! options=$(getopt -o VNnfuswcphdsC: -l virtual-env,no-virtual-env,no-site-packages,force,update,smoke,whitebox,nova-coverage,pep8,help,debug,stdout,config: -- "$@")
+if ! options=$(getopt -o VNnfuswcphdSC: -l virtual-env,no-virtual-env,no-site-packages,force,update,smoke,whitebox,nova-coverage,pep8,help,debug,stdout,config: -- "$@")
 then
     # parse error
     usage