Fix incorrect copy-pasto in error message of pg_waldump.c

The error message used on fclose() failure was incorrect, so fix it.
Oversight in d497093, that I have somehow managed to miss.

src/bin/pg_waldump/pg_waldump.c

@@ -529,7 +529,7 @@ XLogRecordSaveFPWs(XLogReaderState *record, const char *savepath)
 			pg_fatal("could not write file \"%s\": %m", filename);
 
 		if (fclose(file) != 0)
-			pg_fatal("could not write file \"%s\": %m", filename);
+			pg_fatal("could not close file \"%s\": %m", filename);
 	}
 }