Make smoketests working again with Python 2.6/nose

With the switch to testr, the nosetests configuration setting
was lost. Restore.

Change-Id: I55844f6875bdca9cc1f0a63441c4da3d65d92246
diff --git a/run_tests.sh b/run_tests.sh
index 710fbaa..acd9497 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -58,7 +58,7 @@
     -c|--nova-coverage) let nova_coverage=1;;
     -C|--config) config_file=$2; shift;;
     -p|--pep8) let just_pep8=1;;
-    -s|--smoke) testrargs="$testrargs smoke";;
+    -s|--smoke) testrargs+="smoke"; noseargs+="--attr=type=smoke";;
     -t|--serial) serial=1;;
     -l|--logging) logging=1;;
     -L|--logging-config) logging_config=$2; shift;;