Bug 25954: (follow-up) Correct label "for" attribute

Bug 25954: (follow-up) Correct label "for" attribute

This patch updates a couple of search include forms to change the "for"
attribute of the label. Although "idx" is the first field in this
situation, the label's text applies to the keyword field so it should
give focus to the keyword field.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>