ensembl_object_type needs to be reset to NOT NULL

sql/patch_48_49_e.sql

+# patch_48_49_e.sql
+#
+# ensembl_object_type_not_null
+#
+# description:
+# ensembl_object_type not null
+
+ALTER TABLE object_xref CHANGE COLUMN ensembl_object_type
+  ensembl_object_type ENUM('RawContig', 'Transcript', 'Gene',
+                                   'Translation') NOT NULL;
+
+# patch identifier
+INSERT INTO meta (meta_key, meta_value) VALUES ('patch', 'patch_48_49_e.sql|ensembl_object_type_not_null');
+
+
+