fix [#27554] vertex group names

- duplicate vertex group names were not being checked for.
- also made the first duplicate end with .001 rather than .000

source/blender/blenlib/intern/path_util.c

@@ -153,8 +153,10 @@ void BLI_stringenc(char *string, const char *head, const char *tail, unsigned sh
 int BLI_split_name_num(char *left, int *nr, const char *name, const char delim)
 {
 	int a;
-	
-	*nr= 0;
+
+	/* could use '0', but this would mean the first
+	 * duplicate would become FooBar.000 */
+	*nr= 1;
 	a= strlen(name);
 	memcpy(left, name, (a + 1) * sizeof(char));