Bug 16711: OPAC Password recovery: Handling if multiple accounts have the same mail...

Bug 16711: OPAC Password recovery: Handling if multiple accounts have the same mail address

To reproduce:
- Create 3 Accounts, login names are test01, test02, test03, Email is the same
for all.
- Go to OPAC -> Password recovery and indicate E-Mail only
- You will get an email for only one of the accounts above.

To test:
- Apply patch, restart memcached and plack
- Go to db, delete from borrower_password_recovery;
- Try steps above to reproduce. You will get an error message:
    Account identification with this email address only is ambiguous.
    Please use the field 'Login' as well.
- Verify that other cases work as before (provide valid / invalid login only,
  provide valid email for an existing account, provide unknown email, provide
  both login and email with all combinations of valid / invalid)

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Bug 16711: (QA-followup) Use count directly

See comment # 13

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>