vm: allow clean yum cache for dom0 updates (#346)

common/qubes_download_dom0_updates.sh

@@ -4,6 +4,7 @@ DOM0_UPDATES_DIR=/var/lib/qubes/dom0-updates
 
 DOIT=0
 GUI=1
+CLEAN=0
 OPTS="--installroot $DOM0_UPDATES_DIR"
 PKGLIST=
 while [ -n "$1" ]; do
@@ -14,6 +15,9 @@ while [ -n "$1" ]; do
         --nogui)
             GUI=0
             ;;
+        --clean)
+            CLEAN=1
+            ;;
         -*)
             OPTS="$OPTS $1"
             ;;
@@ -32,6 +36,10 @@ fi
 mkdir -p $DOM0_UPDATES_DIR/etc
 cp /etc/yum.conf $DOM0_UPDATES_DIR/etc/
 
+if [ "x$CLEAN" = "1" ]; then
+    yum $OPTS clean all
+fi
+
 if [ "x$PKGLIST" = "x" ]; then
     echo "Checking for dom0 updates..."
     PKGLIST=`yum $OPTS check-update -q | cut -f 1 -d ' '`