File submission fails with HTTP 500 error code.

[nlaney]

The unit test running against the ClamAV rest service has the same inputs as the one running against the local process. The industry standard EICAR-STANDARD-ANTIVIRUS-TEST-FILE fails as expected. However, the unit test fails with an HTTP 500 error code on an empty string and empty byte array, which didn’t fail against the local process. The rest service must not be handling the empty bytes.