zdb -R: do not treat numeric parameters to a flag as more flags

Reviewed by:	Matthew Ahrens <mahrens@delphix.com>
MFC after:	1 week

cddl/contrib/opensolaris/cmd/zdb/zdb.c

@@ -3012,6 +3012,7 @@ zdb_read_block(char *thing, spa_t *spa)
 				free(dup);
 				return;
 			}
+			i += p - &flagstr[i + 1]; /* skip over the number */
 		}
 	}