pg_dump: Remove move "blob" terminology

Commit e9960732a9 accidentally introduced the blob terminology in
error messages which had previously been altered by commit 35ce24c33
from "blob" to "LO". This reverts back to "LO".

Reported-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/20230224.163127.68506240520261483.horikyota.ntt@gmail.com
Discussion: https://www.postgresql.org/message-id/flat/868a381f-4650-9460-1726-1ffd39a270b4%40enterprisedb.com

src/bin/pg_dump/pg_backup_directory.c

@@ -691,13 +691,13 @@ _EndLO(ArchiveHandle *AH, TocEntry *te, Oid oid)
 
 	/* Close the BLOB data file itself */
 	if (EndCompressFileHandle(ctx->dataFH) != 0)
-		pg_fatal("could not close blob data file: %m");
+		pg_fatal("could not close LO data file: %m");
 	ctx->dataFH = NULL;
 
 	/* register the LO in blobs.toc */
 	len = snprintf(buf, sizeof(buf), "%u blob_%u.dat\n", oid, oid);
 	if (CFH->write_func(buf, len, CFH) != len)
-		pg_fatal("could not write to blobs TOC file");
+		pg_fatal("could not write to LOs TOC file");
 }
 
 /*
@@ -711,7 +711,7 @@ _EndLOs(ArchiveHandle *AH, TocEntry *te)
 	lclContext *ctx = (lclContext *) AH->formatData;
 
 	if (EndCompressFileHandle(ctx->LOsTocFH) != 0)
-		pg_fatal("could not close blobs TOC file: %m");
+		pg_fatal("could not close LOs TOC file: %m");
 	ctx->LOsTocFH = NULL;
 }