*with --with-charset=utf8*

Problem: wrong LONG TEXT field length is sent to a client 
when multibyte server character set used.

Fix: always limit field length sent to a client to 2^32,
as we store it in 4 byte slot.

Note: mysql_client_test changed accordingly.


sql/protocol.cc:
  Fix for bug#19829:make test Failed in mysql_client_test 
  *with --with-charset=utf8*
    - limit field length sent to client to UINT_MAX32 as 
      it may exceeds 32 bit slot for LONG TEXT fields if
      thd_charset->mbmaxlen > 1.
tests/mysql_client_test.c:
  Fix for bug#19829:make test Failed in mysql_client_test
  *with --with-charset=utf8*
    - checking field members have in mind that field length
      is limited to UINT_MAX32.