Bug 41040: Empty patron search from the header should not trigger a patron search

If the "arrow" button on the patron search is clicked with no value in
the textbox, it redirects to members/members-home.pl and performs a
search with no value automatically. It makes more send for it to behave
as the "Patrons" link in the navbar that directs to members-home.pl
where the librarian can then perform a more advanced search.

Test Plan:
1) Click the "Search patrons" link on the header, then the arrow button
2) Note an empty patron search is performed immediately
3) Apply this patch
4) Restart all the things!
5) Repeat step 1
6) Note a paton search is no longer triggered automatically

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Laura Escamilla <laura.escamilla@bywatersolutions.com>

members/member.pl

@@ -78,7 +78,7 @@ $template->param(
     searchfieldstype    => $searchfieldstype,
     PatronsPerPage      => C4::Context->preference("PatronsPerPage") || 20,
     circsearch          => $circsearch,
-    defer_loading       => 0,
+    defer_loading       => $searchmember ? 0 : 1,
 );
 
 output_html_with_http_headers $input, $cookie, $template->output;