[FIX] users_ldap: consistent handling of login() vs check()

Explicit check for blank passwords was introduced recently
in check() for bug 760301, but login() did not behave the same
so the resulting error message would be inconsistent.

lp bug: https://launchpad.net/bugs/760301 fixed

bzr revid: odo@openerp.com-20110616160219-m0y066q914s4y7ev

addons/users_ldap/users_ldap.py

@@ -70,6 +70,11 @@ res_company()
 class users(osv.osv):
     _inherit = "res.users"
     def login(self, db, login, password):
+
+        if not password:
+            # empty passwords are disallowed for obvious security reasons
+            return False
+
         ret = super(users,self).login(db, login, password)
         if ret:
             return ret