Modify search endpoint to accept sha256 (sample_id) param and fix return value for ssdeep_group.
Modify search endpoint to accept sha256 (sample_id) param and fix return value for ssdeep_group.

Other changes:
  - change param dict access to use .get to avoid KeyError

MITRECND/multiscanner,awest1339/multiscanner,jmlong1027/multiscanner,mitre/multiscanner,jmlong1027/multiscanner,jmlong1027/multiscanner,awest1339/multiscanner,awest1339/multiscanner,MITRECND/multiscanner,awest1339/multiscanner,jmlong1027/multiscanner,mitre/multiscanner,mitre/multiscanner