Bug 16707: Fix software error in OPAC password recovery when leaving form fields...

Bug 16707: Fix software error in OPAC password recovery when leaving form fields empty

The $search_results is considered as an arrayref but is not defined if
no patron matches the recovery infos.

Test plan:
- Set syspref OpacResetPassword to "Allow"
- Go to OPAC
- Click link "Forgot your password?
- On the following screen "Forgotten password recovery", do not fill in
  form fields, click "Submit"
=> Without this patch you got the software error
=> With this patch apply, you will get "No account was found with the
provided information."

Sign-off on counter patch.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>