grubby-bls: unset default entry if is the one being removed

If the default entry is removed, this can't be set as the default anymore
for zipl. Otherwise the zipl tool will fail since it won't exist an IPL
section for the one set as the default.

For grub2, if the saved_entry doesn't exist it will fallback to the first
entry. But still the correct thing to do is to unset the default there.

Resolves: rhbz#1668329

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>

grubby-bls

@@ -305,6 +305,15 @@ grub_class kernel${flavor}
 EOF
 }
 
+unset_default_bls()
+{
+    if [[ $bootloader = grub2 ]]; then
+        grub2-editenv "${env}" unset saved_entry
+    else
+        sed -i -e "/^default=.*/d" "${zipl_config}"
+    fi
+}
+
 remove_bls_fragment() {
     local indexes=($(param_to_indexes "$1"))
 
@@ -313,6 +322,9 @@ remove_bls_fragment() {
     fi
 
     for i in "${indexes[@]}"; do
+        if [[ $default_index = $i ]]; then
+            unset_default_bls
+        fi
         rm -f "${bls_file[$i]}"
     done