Fix binary/utf8 issues with Differential changeset parse cache

Summary:
Fixes T4898. After we increased the strictness of the `%s` conversion, most `serialize()` output is rejected from the cache.

Drop the cache, change the column type to latin1_bin, and then use `%B` to mark the data as binary during query construction.

Test Plan: Viewed Differential, saw cache fills.

Reviewers: btrahan, spicyj

Reviewed By: spicyj

Subscribers: epriestley

Maniphest Tasks: T4898

Differential Revision: https://secure.phabricator.com/D9171

resources/sql/autopatches/20140517.dxbinarycache.sql

@@ -0,0 +1,4 @@
+TRUNCATE {$NAMESPACE}_differential.differential_changeset_parse_cache;
+
+ALTER TABLE {$NAMESPACE}_differential.differential_changeset_parse_cache
+  CHANGE cache cache LONGTEXT COLLATE latin1_bin NOT NULL;