Comment 3 for bug 610525

This is work for Yasufumi:
1:
btr/btr0btr.c: In function ‘btr_discard_only_page_on_level’:
btr/btr0btr.c:2911: warning: null argument where non-null required (argument 1)
btr/btr0cur.c: In function ‘btr_cur_update_alloc_zip’:
btr/btr0cur.c:1834: warning: null argument where non-null required (argument 2)
btr/btr0cur.c:1853: warning: null argument where non-null required (argument 1)
btr/btr0cur.c: In function ‘btr_cur_update_in_place’:
btr/btr0cur.c:1960: warning: null argument where non-null required (argument 1)
2:
buf/buf0buf.c: In function ‘_increment_page_get_statistics’:
buf/buf0buf.c:86: warning: comparison is always false due to limited range of data type
buf/buf0buf.c: In function ‘buf_chunk_init’:
buf/buf0buf.c:840: warning: ‘zip_hash_tmp’ may be used uninitialized in this function
3:
fil/fil0fil.c: In function ‘fil_open_single_table_tablespace’:
fil/fil0fil.c:3128: warning: pointer targets in passing argument 2 of ‘dict_table_get_index_on_name’ differ in signedness
4:
ibuf/ibuf0ibuf.c: In function ‘ibuf_set_free_bits_low’:
ibuf/ibuf0ibuf.c:792: warning: null argument where non-null required (argument 1)
ibuf/ibuf0ibuf.c: In function ‘ibuf_update_free_bits_zip’:
ibuf/ibuf0ibuf.c:967: warning: null argument where non-null required (argument 1)