kernel-install: prefer /boot over /boot/efi for $BOOT_ROOT

This restores the preference order from before 9e82a74. The code
previous to that change 'preferred' /boot over /boot/efi; that
commit changed it to check /boot/efi before checking /boot.
Changing this precedence could (and did, for me) have unexpected
effects - it seems safer to leave it how it was.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

src/kernel-install/kernel-install

@@ -108,7 +108,7 @@ fi
 [ -z "$MACHINE_ID" ] && MACHINE_ID="Default"
 
 [ -z "$BOOT_ROOT" ] && for suff in "$MACHINE_ID" "loader/entries"; do
-    for pref in "/efi" "/boot/efi" "/boot"; do
+    for pref in "/efi" "/boot" "/boot/efi" ; do
         if [ -d "$pref/$suff" ]; then
             BOOT_ROOT="$pref"
             break 2