Creating directory before attempting to create file for detection.

Error solved:

```
IFile "lib/python2.7/site-packages/thumbor/storages/file_storage.py", line 64, in put_detector_data
IOError: [Errno 2] No such file or directory: '/path/to/file/ba/4ed3bf706f2efff35373ae03b52f850bd3a695.detectors.txt.e666f83dd1f94f96925b79f9ee272ebe'
```
This error occurs only when the storage configuration is as follows:
```python
MIXED_STORAGE_FILE_STORAGE = 'thumbor.storages.no_storage'
MIXED_STORAGE_CRYPTO_STORAGE = 'thumbor.storages.no_storage'
MIXED_STORAGE_DETECTOR_STORAGE = 'thumbor.storages.file_storage'
```
if MIXED_STORAGE_FILE_STORAGE is enabled for file cache, the folder already exists when will save the detection