Make IMPORT FOREIGN SCHEMA behave consistently

The case of the table names returned by information_schema queries
depends on MySQL's `lower_case_table_names` setting.
https://dev.mysql.com/doc/refman/5.7/en/charset-collation-information-schema.html
suggests forcing a suitable collation to work around the issue.

Fixes #202.

mysql_fdw.c

@@ -1699,7 +1699,7 @@ mysqlImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
  {
  bool first_item = true;
 
- appendStringInfoString(&buf, " AND t.TABLE_NAME ");
+ appendStringInfoString(&buf, " AND t.TABLE_NAME COLLATE UTF8_GENERAL_CI ");
  if (stmt->list_type == FDW_IMPORT_SCHEMA_EXCEPT)
  appendStringInfoString(&buf, "NOT ");
  appendStringInfoString(&buf, "IN (");