[PBCKP-227]: Remove get_system_dbstate declaration from header file

Author: dlepikhova

src/pg_probackup.h

@@ -1158,7 +1158,6 @@ extern uint64 get_system_identifier(const char *pgdata_path, fio_location locati
 extern uint64 get_remote_system_identifier(PGconn *conn);
 extern uint32 get_data_checksum_version(bool safe);
 extern pg_crc32c get_pgcontrol_checksum(const char *pgdata_path);
-extern DBState get_system_dbstate(const char *pgdata_path, fio_location location);
 extern uint32 get_xlog_seg_size(const char *pgdata_path);
 extern void get_redo(const char *pgdata_path, fio_location pgdata_location, RedoParams *redo);
 extern void set_min_recovery_point(pgFile *file, const char *backup_path,