Fix minor error message style guide violation.

No periods at the ends of primary error messages, please.

Daniel Gustafsson

Discussion: https://postgr.es/m/43E004C0-18C6-42B4-A313-003B43EB0571@yesql.se

src/backend/access/transam/xlog.c

@@ -4750,11 +4750,11 @@ ReadControlFile(void)
 	/* check and update variables dependent on wal_segment_size */
 	if (ConvertToXSegs(min_wal_size_mb, wal_segment_size) < 2)
 		ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						errmsg("\"min_wal_size\" must be at least twice \"wal_segment_size\".")));
+						errmsg("\"min_wal_size\" must be at least twice \"wal_segment_size\"")));
 
 	if (ConvertToXSegs(max_wal_size_mb, wal_segment_size) < 2)
 		ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						errmsg("\"max_wal_size\" must be at least twice \"wal_segment_size\".")));
+						errmsg("\"max_wal_size\" must be at least twice \"wal_segment_size\"")));
 
 	UsableBytesInSegment =
 		(wal_segment_size / XLOG_BLCKSZ * UsableBytesInPage) -