Bug 11419: display Z39.50 search errors more completely

Bug 11419: display Z39.50 search errors more completely

When a z39.50 server isn't able to be searched successfully, the yellow
error box came up empty.  This patch fixes the problem.

Test Plan:
1) Go to Administration/z39.50 servers
2) Create a fake z39.50 server with a made up address
3) Go to cataloging, search only that server
4) Note the empty yellow alert box
5) Apply this patch
6) Re-run the search, not the alert box has a message in it now

Signed-off-by: Nora Blake <nblake@masslibsystem.org>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes all tests and QA script.
Works according to test plan.
When one of the selected servers gives result no dialog
box is shown before and after applying the patch.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 0fc114eee3f649abea88a62502211c595c2867b8)
Signed-off-by: Fridolin SOMERS <fridolin.somers@biblibre.com>