Fix for BUG#14272: Don't run index scan when we should use quick select.

This could cause failures because there are table handlers (like federated)
that support quick select scanning but do not support index scanning.
 


mysql-test/t/disabled.def:
  Enabled federated testcase.

mysql-test/t/disabled.def

@@ -15,4 +15,3 @@ rpl_relayrotate : Unstable test case, bug#12429
 rpl_until       : Unstable test case, bug#12429
 rpl_deadlock    : Unstable test case, bug#12429
 kill            : Unstable test case, bug#9712
-federated       : Broken test case, bug#14272

sql/sql_update.cc

@@ -286,7 +286,7 @@ int mysql_update(THD *thd,
     if (used_index < MAX_KEY && old_used_keys.is_set(used_index))
     {
       table->key_read=1;
-      table->file->extra(HA_EXTRA_KEYREAD); //todo: psergey: check
+      table->file->extra(HA_EXTRA_KEYREAD);
     }
 
     /* note: can actually avoid sorting below.. */
@@ -334,7 +334,7 @@ int mysql_update(THD *thd,
       /* If quick select is used, initialize it before retrieving rows. */
       if (select && select->quick && select->quick->reset())
         goto err;
-      if (used_index == MAX_KEY)
+      if (used_index == MAX_KEY || (select && select->quick))
         init_read_record(&info,thd,table,select,0,1);
       else
         init_read_record_idx(&info, thd, table, 1, used_index);