Clean up assertion in get_boot_devices_list()

g_strdup() can't fail, remove assertion.  Assert its argument can't be
null, because that's not obvious (add_boot_device_path() ensures it).
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

vl.c

@@ -915,8 +915,8 @@ char *get_boot_devices_list(uint32_t *size)
         } else if (devpath) {
             bootpath = devpath;
         } else {
+            assert(i->suffix);
             bootpath = g_strdup(i->suffix);
-            assert(bootpath);
         }
 
         if (total) {