Revert "Revert "ITS#8240""

We have never documented our use of assert, so can't expect
builders to do the right thing.
This reverts commit c5b4cd67.

CHANGES

 OpenLDAP 2.4 Change Log
 
 OpenLDAP 2.4.43 Engineering
+	Fixed liblber remove obsolete assert (ITS#8240)
 	Fixed slap tools minor one time memory leak (ITS#8082)
 	Fixed slapd to avoid redundant processing of abandon ops (ITS#8232)
 	Fixed slapd syncrepl segv when present list is NULL (ITS#8231, ITS#8042)

libraries/liblber/io.c

@@ -679,7 +679,7 @@ done:
 		return (ber->ber_tag);
 	}
 
-	assert( 0 ); /* ber structure is messed up ?*/
+	/* invalid input */
 	return LBER_DEFAULT;
 }