[BitBucket user: Sin-Di Lee]
[BitBucket date: 2017-03-30.09:27:00]

When we export a study with two equal name series via zip file format, only one of the series was exported successfully and the other was overwrote.

On the other hand, if we choose DICOMDIR format, both of the two series were exported successfully.

Environment:
* Orthanc 1.2.0
* Windows 10