Redirect dpkg -l stderr to /dev/null

Fixes bug 1211413

Change-Id: I33a7e1e8fb3755c69ca0570e333e4908cb6f3da4
diff --git a/functions b/functions
index e9c6061..6ae650e 100644
--- a/functions
+++ b/functions
@@ -909,7 +909,7 @@
     fi
 
     if [[ "$os_PACKAGE" = "deb" ]]; then
-        dpkg -l "$@" > /dev/null
+        dpkg -l "$@" > /dev/null 2> /dev/null
     elif [[ "$os_PACKAGE" = "rpm" ]]; then
         rpm --quiet -q "$@"
     else