grub.cfg: search usb *last*, in the main menuentry

There is already a separate menuentry for USB, and most people don't boot their
installed system from USB anyway. This will result in faster boot speeds.

resources/grub/config/grub.cfg

@@ -97,9 +97,9 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 # unnecessary decryption routines in the following order:
 
 #	1) raw devices and MBR/GPT partitions
-    search_grub usb
 	search_grub ahci
-    search_grub ata
+	search_grub ata
+    	search_grub usb
 #	2) LVM and RAID which might be used accross multiple devices
 	unset lvmvol
 	for vol in bootvol rootvol; do
@@ -146,7 +146,7 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 	fi
 	set pager=0
 	echo -n "Attempting to cryptomount: "
-	for dev in ${usbdev} ${ahcidev} ${atadev} ${lvmvol}; do # what about raid?
+	for dev in ${ahcidev} ${atadev} ${lvmvol} ${usbdev}; do # what about raid?
 		echo -n "${dev} "
 		if cryptomount "${dev}" ; then break ; fi
 	done