Bug 20240: Remove space before : when searching for a vendor in serials (Vendor name :)

Bug 20240: Remove space before : when searching for a vendor in serials (Vendor name :)

This patch removes the space before the colon in the "vendor" label in
the vendor search pop-up window.

To test, apply the patch and go to Serials -> New subscription.

- Click the "Search for a vendor" link next to the vendor form field.
- In the pop-up window, confirm that there is no space before the colon
  in the "vendor" label.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>