Removed min and target version from manifest

We don't need to set min and target version here as it is already defined in the [build.gradle](https://github.com/guerwan/TransitionsBackport/blob/master/library/build.gradle#L20-L21).
Plus it should fix 

```
Execution failed for task ':MyApp:processDebugManifest'.
> Manifest merging failed. See console for more info.
Main manifest has <uses-sdk android:minSdkVersion='10'> but library uses minSdkVersion='14'
```