bug-1402776 WIP. Still need to write a test

bin/pt-query-digest

@@ -4706,11 +4706,14 @@ sub parse_client_handshake_packet {
       return;
    }
 
-   my $code_len = hex($buff_len);
+   my $code_len = hex($buff_len);               
+   # The (.*?)00.?\Z part in the regex, is to remove an erroneous 
+   # null char + mysql_native_password after the db name
+   # https://bugs.launchpad.net/percona-toolkit/+bug/1402776
    my ( $db ) = $data =~ m!
       ^.{64}${user}00..   # Everything matched before
       (?:..){$code_len}   # The scramble buffer
-      (.*)00\Z            # The database name
+      (.*?)00.*\Z            # The database name
    !x;
    my $pkt = {
       user  => to_string($user),