Updated changelog [skip-ci]

Author: smarek

CHANGELOG.md

@@ -7,6 +7,8 @@
   - FileAsyncHttpResponseHandler now checks that target file path is available or can be created
   - DataAsyncHttpResponseHandler was sending cancel notification instead of progress notification, fixed
   - Added support for HTTP PATCH requests
+  - Fixed Assert exception when mkdirs in FileAsyncHttpResponseHandler tries to create dirs that already exists
+  - Provided option to easily override ClientConnectionManager provision in AsyncHttpClient
 
 ## 1.4.6 (released 7. 9. 2014)