Bug 1389456 - Add ppapi/ to the thirdparty list r=peterv

MozReview-Commit-ID: KIcJ64Y0207

--HG--
extra : rebase_source : 57fc47deb7f056e66663bc1b7819671ff4d9a706

tools/rewriting/ThirdPartyPaths.txt

@@ -1,4 +1,5 @@
 browser/components/translation/cld2/
+browser/extensions/mortar/ppapi/
 db/sqlite3/src/
 dom/media/platforms/ffmpeg/libav
 extensions/spellcheck/hunspell/src/