Pt 2075 fix tests for pt stalk (#541)

* Added mysql.proxies_priv to list of exceptions from checks in Sandbox.pm

* Fixed test for slave_status for 5.7+

lib/Sandbox.pm

@@ -371,6 +371,7 @@ sub verify_test_data {
                           grep { !/server_cost$/ }
                           grep { !/tables_priv$/ }
                           grep { !/user$/ }
+                          grep { !/proxies_priv$/ }
                           @{$master->selectcol_arrayref('SHOW TABLES FROM mysql')};
    my @tables_in_sakila = qw(actor address category city country customer
                              film film_actor film_category film_text inventory

t/pt-stalk/pt-stalk.t

@@ -755,7 +755,7 @@ SKIP: {
    
    like(
       $output,
-      qr/Slave has read all relay log; waiting for more updates/,
+      qr/SERVICE_STATE: ON/,
       "MySQL 5.7 SLAVE STATUS"
    ) or diag ($output);
    $sb->stop_sandbox(qw(chan_master1 chan_master2 chan_slave1));