res_config_odbc: Use dynamically sized buffers to store row data so values do not get truncated.

ASTERISK-23582 #close
ASTERISk-23582 #comment Reported by: Walter Doekes

Review: https://reviewboard.asterisk.org/r/3557/
........

Merged revisions 414693 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 414694 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@414695 f38db490-d61c-443f-a65b-d21fe96a405b