Add a master_response_timeout parameter and use it to limit the amount

of time we spent a reponse from master before declaring the failure.
Also, change is_pgup() so it use PQsendQuery() instead of PQexec to
execute the check of master

config.h

@@ -36,6 +36,7 @@ typedef struct
 	char loglevel[MAXLEN];
 	char logfacility[MAXLEN];
 	char rsync_options[QUERY_STR_LEN];
+	int  master_response_timeout;
 } t_configuration_options;
 
 void parse_config(const char *config_file, t_configuration_options *options);