added syntax:
  'show variables where', 'show status where', 'show open tables where'


mysql-test/r/grant_cache.result:
  wl#1629 SHOW with WHERE(final part,after review)
mysql-test/r/information_schema.result:
  wl#1629 SHOW with WHERE(final part,after review)
mysql-test/r/query_cache.result:
  wl#1629 SHOW with WHERE(final part,after review)
mysql-test/r/temp_table.result:
  wl#1629 SHOW with WHERE(final part,after review)
mysql-test/r/union.result:
  wl#1629 SHOW with WHERE(final part,after review)
mysql-test/t/information_schema.test:
  wl#1629 SHOW with WHERE(final part,after review)
mysql-test/t/query_cache.test:
  wl#1629 SHOW with WHERE(final part,after review)
sql/item.cc:
  wl#1629 SHOW with WHERE(final part,after review)
sql/mysql_priv.h:
  wl#1629 SHOW with WHERE(final part,after review)
sql/sql_parse.cc:
  wl#1629 SHOW with WHERE(final part,after review)
sql/sql_select.cc:
  wl#1629 SHOW with WHERE(final part,after review)
sql/sql_show.cc:
  wl#1629 SHOW with WHERE(final part,after review)
sql/sql_yacc.yy:
  wl#1629 SHOW with WHERE(final part,after review)
sql/table.h:
  wl#1629 SHOW with WHERE(final part,after review)