Bug 31967: Search terms retained in header search when only one result

Bug 31967: Search terms retained in header search when only one result

Bug 26247 added a system preference to manage the Retaining of search terms in header search.
But this does not work if there is only one match and you go directly to details page.

Test plan :
1) Set system preference RetainCatalogSearchTerms to "Don't retain"
2) Perform a search leading to a single result.
   For example in KTD the ISBN 1932100083
=> Without patch search bar is populated with search terms
=> With patch search bar is not populated with search terms

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>