Fix coverity defects: CID 186143

CID 186143: Memory - illegal accesses (USE_AFTER_FREE)

This patch fixes an use-after-free in spa_import_progress_destroy()
moving the kmem_free() call at the end of the function.

Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Reviewed-by: Giuseppe Di Natale <guss80@gmail.com>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #8788

module/zfs/spa_misc.c

@@ -2102,8 +2102,8 @@ spa_import_progress_destroy(void)
 	spa_history_list_t *shl = spa_import_progress_list;
 	procfs_list_uninstall(&shl->procfs_list);
 	spa_import_progress_truncate(shl, 0);
-	kmem_free(shl, sizeof (spa_history_list_t));
 	procfs_list_destroy(&shl->procfs_list);
+	kmem_free(shl, sizeof (spa_history_list_t));
 }
 
 int