Bug 1388046 - Disable sandbox read restrictions (level 3) on beta/release. r=jld

MozReview-Commit-ID: 3VQM545aqpL

--HG--
extra : rebase_source : 75d2091dd3cb99027091247bfc90358e3cb8d440

browser/app/profile/firefox.js

@@ -1096,7 +1096,11 @@ pref("security.sandbox.content.level", 3);
 //
 // This setting may not be required anymore once we decide to permanently
 // enable the content sandbox.
+#ifdef NIGHTLY_BUILD
 pref("security.sandbox.content.level", 3);
+#else
+pref("security.sandbox.content.level", 2);
+#endif
 pref("security.sandbox.content.write_path_whitelist", "");
 pref("security.sandbox.content.read_path_whitelist", "");
 pref("security.sandbox.content.syscall_whitelist", "");