pidgin/pidgin

Fix leak in `purple_markup_find_tag` on error
release-2.x.y
2021-09-15, Elliott Sales de Andrade
addb2327cde0
Fix leak in `purple_markup_find_tag` on error

The output is set to `NULL`, but the internal data list is not freed if it happened to get something put into it.

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35816

Testing Done:
Ran `pidgin_utils_fuzzer` on the test case in the bug report.

Reviewed at https://reviews.imfreedom.org/r/924/
/** @page ui-ops UiOps structures
When implementing a UI for libpurple, you need to fill in various UiOps
structures:
- #PurpleAccountUiOps
- #PurpleBlistUiOps
- #PurpleConnectionUiOps
- #PurpleConversationUiOps
- #PurpleCoreUiOps
- #PurpleDebugUiOps
- #PurpleDnsQueryUiOps
- #PurpleEventLoopUiOps (without this, nothing will work and you will cry)
- #PurpleIdleUiOps
- #PurpleNotifyUiOps
- #PurplePrivacyUiOps
- #PurpleRequestUiOps
- #PurpleRoomlistUiOps
- #PurpleSoundUiOps
- #PurpleWhiteboardUiOps
- #PurpleXferUiOps
*/
// vim: ft=c.doxygen