Bug 1217261 - Bump clobber for rust changes. r=kinetik

Last time we had a linker issue when we changed the rust code.
Until we track that down, avoid blocking inbound.

CLOBBER

@@ -22,4 +22,4 @@
 # changes to stick? As of bug 928195, this shouldn't be necessary! Please
 # don't change CLOBBER for WebIDL changes any more.
 
-Bug 1215696 - Update mp4parse to v0.1.1
+Bug 1217261 - Update mp4parse to v0.1.2