Fix: mistake in login selection which would cause false positive error

src/archlabs-installer

@@ -69,6 +69,7 @@ DBG="/tmp/debuglog"                   # debug log when passed -d
 RUN="/run/archiso/bootmnt/arch/boot"  # path for live /boot
 BT="$DIST Installer - v$VER"          # backtitle used for dialogs
 VM="$(dmesg | grep -i "hypervisor")"  # is the system a vm
+SEL=0                                 # currently selected menu item
 
 AUTO_ROOT_PART=""   # values from auto partition
 AUTO_BOOT_PART=""
@@ -215,9 +216,7 @@ declare -A FS_OPTS=(
 
 main()
 {
-    [[ $SEL ]] || SEL=0
     (( SEL < 11 )) && (( SEL++ ))
-
     tput civis
     SEL=$(dialog --cr-wrap --stdout --backtitle "$BT" \
         --title " $_PrepTitle " --default-item $SEL \
@@ -234,9 +233,7 @@ main()
         "10" "$_PrepShow" \
         "11" "$_PrepInstall")
 
-    if [[ $WARN != true && $SEL =~ (2|5) ]]; then
-        WARN=true; msgbox "$_PrepTitle" "$_WarnMount"
-    fi
+    [[ $WARN != true && $SEL =~ (2|5) ]] && { WARN=true; msgbox "$_PrepTitle" "$_WarnMount"; }
 
     case $SEL in
         1) device_tree ;;
@@ -515,7 +512,7 @@ select_login()
         "xinit"   "Console login without a display manager" \
         "lightdm" "Lightweight display manager with a gtk greeter")"
 
-    if [[ $LOGIN_TYPE ]]; then
+    if [[ $LOGIN_TYPE == "" ]]; then
         return 1
     elif [[ $LOGIN_TYPE == 'lightdm' ]]; then
         WM_PACKAGES+=" lightdm lightdm-gtk-greeter lightdm-gtk-greeter-settings accountsservice"