Bug 25235: Rename the button instead of alerting when replacing an existing record

Bug 25235: Rename the button instead of alerting when replacing an existing record

Test plan:

Pre-patch
1 - Go to the main Authorities page, search for any authority, click
    the Actions menubutton and choose Edit
2 - Note the button saying Z39.50 search
3 - Note the modal alert forcing you to click it
4 - Cancel and cancel again, and in the New authority menubutton choose
    Default
5 - Click the button saying Z39.50 search again, note that it warns you
    about replacing your totally blank record

Apply this patch
6 - Edit an existing authority, note the button says "Replace record via
    Z39.50/SRU search"
2 - Click the button, verify it still opens the search window with the
    main entry of the record filled in without an alert
3 - Create a new authority, note the button says "Z39.50/SRU search"
4 - Click the button, verify it still opens the search window but
    without an alert

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>