Bug#17661 information_schema.SCHEMATA returns uppercase with lower_case_table_names = 1

fix: return db name for I_S.TABLES(and others) in original letter case.
if mysql starts with lower_case_table_names=1 | 2 then original db name is converted
to lower case(for I_S tables). It happens when we perform add_table_to_list. 
to avoid this we make a copy of original db name and use the copy hereafter.

mysql-test/r/lowercase_table2.result

@@ -165,3 +165,12 @@ create table t1Aa (col1 int);
 select t1Aa.col1 from t1aA,t2Aa where t1Aa.col1 = t2aA.col1;
 col1
 drop table t2aA, t1Aa;
+create database mysqltest_LC2;
+use mysqltest_LC2;
+create table myUC (i int);
+select TABLE_SCHEMA,TABLE_NAME FROM information_schema.TABLES
+where TABLE_SCHEMA ='mysqltest_LC2';
+TABLE_SCHEMA	TABLE_NAME
+mysqltest_LC2	myUC
+use test;
+drop database mysqltest_LC2;

mysql-test/t/lowercase_table2.test

@@ -139,3 +139,14 @@ select t1Aa.col1 from t1aA,t2Aa where t1Aa.col1 = t2aA.col1;
 drop table t2aA, t1Aa;
 
 # End of 4.1 tests
+
+#
+# Bug#17661 information_schema.SCHEMATA returns uppercase with lower_case_table_names = 1
+#
+create database mysqltest_LC2;
+use mysqltest_LC2;
+create table myUC (i int);
+select TABLE_SCHEMA,TABLE_NAME FROM information_schema.TABLES
+where TABLE_SCHEMA ='mysqltest_LC2';
+use test;
+drop database mysqltest_LC2;

sql/sql_show.cc

@@ -2070,7 +2070,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
   ST_SCHEMA_TABLE *schema_table= tables->schema_table;
   SELECT_LEX sel;
   INDEX_FIELD_VALUES idx_field_vals;
-  char path[FN_REFLEN], *end, *base_name, *file_name;
+  char path[FN_REFLEN], *end, *base_name, *orig_base_name, *file_name;
   uint len;
   bool with_i_schema;
   enum enum_schema_tables schema_table_idx;
@@ -2150,7 +2150,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
 
   partial_cond= make_cond_for_info_schema(cond, tables);
   it.rewind(); /* To get access to new elements in basis list */
-  while ((base_name= it++) ||
+  while ((orig_base_name= base_name= it++) ||
 	 /*
 	   generate error for non existing database.
 	   (to save old behaviour for SHOW TABLES FROM db)
@@ -2181,6 +2181,8 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
         if (mysql_find_files(thd, &files, base_name, 
                              path, idx_field_vals.table_value, 0))
           goto err;
+        if (lower_case_table_names)
+          orig_base_name= thd->strdup(base_name);
       }
 
       List_iterator_fast<char> it_files(files);
@@ -2249,7 +2251,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
               in this case.
             */
             res= schema_table->process_table(thd, show_table_list, table,
-                                             res, base_name,
+                                             res, orig_base_name,
                                              show_table_list->alias);
             close_tables_for_reopen(thd, &show_table_list);
             DBUG_ASSERT(!lex->query_tables_own_last);