Meta: Fix shellcheck errors in build-image-qemu.sh

Author: https://github.com/linusg
Commit: https://github.com/SerenityOS/serenity/commit/fbc1448eab
Pull-request: https://github.com/SerenityOS/serenity/pull/13951
Reviewed-by: https://github.com/IdanHo
Reviewed-by: https://github.com/gmta ✅

Meta/build-image-qemu.sh

@@ -110,9 +110,9 @@ fi
 
 if [ $USE_EXISTING -eq 1 ];  then
     OLD_DISK_SIZE_BYTES=$(wc -c < _disk_image)
-    if [ $DISK_SIZE_BYTES -gt "$OLD_DISK_SIZE_BYTES" ]; then
+    if [ "$DISK_SIZE_BYTES" -gt "$OLD_DISK_SIZE_BYTES" ]; then
         echo "resizing disk image..."
-        qemu-img resize -f raw _disk_image $DISK_SIZE_BYTES || die "could not resize disk image"
+        qemu-img resize -f raw _disk_image "$DISK_SIZE_BYTES" || die "could not resize disk image"
         if ! resize2fs _disk_image; then
             rm -f _disk_image
             USE_EXISTING=0
@@ -124,7 +124,7 @@ fi
 
 if [ $USE_EXISTING -ne 1 ]; then
     printf "setting up disk image... "
-    qemu-img create -q -f raw _disk_image $DISK_SIZE_BYTES || die "could not create disk image"
+    qemu-img create -q -f raw _disk_image "$DISK_SIZE_BYTES" || die "could not create disk image"
     chown "$SUDO_UID":"$SUDO_GID" _disk_image || die "could not adjust permissions on disk image"
     echo "done"