Bug 13238: Improve heading on vendor search when searching for all vendors

 Bug 13238: Improve heading on vendor search when searching for all vendors

To test:
1) Go to Acquisitions and do an empty vendor search
2) Should now read "Vendor search: X results found"
3) Enter a search term and search for vendor
4) Should now read "Vendor search: Y results found for 'search term'"

Sponsored-by: Catalyst IT
NOTE: two nested if/else/end's could make it result/results,
      as suggested in comment #3. However, this meets my understanding
      of the problem as defined in comment #0.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>