Fix potential buffer overflows from invalid string size arguments

- FILENAME_MAX was used when the output was later limited by FILE_MAX.
- Some were passing in incorrect/dummy sizes in a couple of places.

source/blender/blenkernel/intern/bpath.c

@@ -531,7 +531,7 @@ static bool absolute_convert_foreach_path_cb(BPathForeachPathData *bpath_data,
     return false; /* Already absolute. */
   }
 
-  BLI_strncpy(path_dst, path_src, FILENAME_MAX);
+  BLI_strncpy(path_dst, path_src, FILE_MAX);
   BLI_path_abs(path_dst, data->basedir);
   if (BLI_path_is_rel(path_dst) == false) {
     data->count_changed++;