libvect: fix bug in Vect_get_full_name() - OGR direct

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@39901 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/vector/Vlib/header.c

@@ -227,7 +227,9 @@ const char *Vect_get_full_name(const struct Map_info *Map)
 {
     char *ptr;
 
-    if (Map->format == GV_FORMAT_OGR_DIRECT) {
+    if (Map->format == GV_FORMAT_OGR_DIRECT &&
+	Map->fInfo.ogr.dsn &&
+	Map->fInfo.ogr.layer_name) {
 	ptr = (char *) G_malloc(strlen(Map->fInfo.ogr.layer_name) +
 				strlen(Map->fInfo.ogr.dsn) + 2);	
 	sprintf(ptr, "%s@%s", Map->fInfo.ogr.layer_name,