Unexplicit throw in MinibatchInferenceLoop if batch_size is larger than dataset size

[pabfer]

Describe the bug

If batch_size for MinibatchInferenceLoop is larger than the dataset size, this line throws due to division by zero.

Expected behavior

Possible mitigations are:

• Option No. 1: Default batch size to min("requested batch size", "dataset size") and issue a warning if "requested batch size" > "dataset size".
• Option No. 2: Throw with a message stating why it's throwing and how to fix the issue.

Desktop:

• OS: Ubuntu 18.04.2
• Python version: 3.6
• MXNet version: 1.4.1
• MXFusion version: 0.3.1
• MXNet context: CPU

[DerrickGXD]

thank you for issuing this problem. I have created a pull request to resolve this in the deploy branch.