Added uptime to stc-warden.

Change-Id: I19acabb6b6b847f706a5a684f94b1fc3ad2b23bd
diff --git a/tools/test/bin/stc-warden b/tools/test/bin/stc-warden
index 24a924a..f70bfbe 100755
--- a/tools/test/bin/stc-warden
+++ b/tools/test/bin/stc-warden
@@ -13,6 +13,8 @@
     echo "$slave:"
     ssh sdn@$slave "touch foo && echo 'Disk OK' || echo 'Disk READ-ONLY'"
     let ok=ok+$?
+    ssh sdn@$slave "uptime"
+    let ok=ok+$?
     ssh sdn@$slave "df -h /"
     let ok=ok+$?
     ssh sdn@$slave sudo lxc-ls --fancy