kdumpctl: check force[_no]_rebuild when do estimate

Use need_initrd_rebuild() instead of is_system_modified to
check if the initrd needs to be rebuilt during do_estimate,
it checks whether force_rebuild or force_no_rebuild is used.

Signed-off-by: Lichen Liu <lichliu@redhat.com>

Author: licliu

kdumpctl

@@ -1531,8 +1531,9 @@ do_estimate()
 	local kernel_size mod_size initrd_size baseline_size runtime_size reserved_size estimated_size recommended_size _cryptsetup_overhead
 	local size_mb=$((1024 * 1024))
 
-	setup_initrd
-	is_system_modified
+	parse_config || return 1
+	setup_initrd || return 1
+	need_initrd_rebuild
 	case "$?" in
 	0)
 		# Nothing to do