Fix a typo and use blkid flags

Instead of using grep and cut use only the blkid flags to output
SWAP_DRIVES.

base/etc/one-context.d/04-mount-swap

@@ -2,7 +2,7 @@
 
 activate_swaps() {
 
-    SWAP_DRIVES=$(blkid | grep 'TYPE=\"swap\"' | cut -d':' -f1)
+    SWAP_DRIVES=$(blkid -t TYPE="swap" -o device)
     for SWAP in $SWAP_DRIVES ; do
         if [ -z "$(swapon -s | grep $SWAP)" ]; then
             swapon $SWAP