Fix the init value for repl_id of rdbSaveInfo struct (#8026)

use 40 zeros rather than 30 zeros to match CONFIG_RUN_ID_SIZE.
this doesn't have any real implications.

src/server.h

@@ -1014,7 +1014,7 @@ typedef struct rdbSaveInfo {
     long long repl_offset;                  /* Replication offset. */
 } rdbSaveInfo;
 
-#define RDB_SAVE_INFO_INIT {-1,0,"000000000000000000000000000000",-1}
+#define RDB_SAVE_INFO_INIT {-1,0,"0000000000000000000000000000000000000000",-1}
 
 struct malloc_stats {
     size_t zmalloc_used;