Avoid complaining about empty directories

Change-Id: If46bffd1c4e6b94f2e476b2d7d506ef337bbf8e1
diff --git a/envsetup.sh b/envsetup.sh
index f1e7101..0cf4ef4 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -197,7 +197,7 @@
 
     dir="sdk/bash_completion"
     if [ -d ${dir} ]; then
-        for f in ${dir}/[a-z]*.bash; do
+        for f in `/bin/ls ${dir}/[a-z]*.bash 2> /dev/null`; do
             echo "including $f"
             . $f
         done