Added test case for POLICY_KEY_DIGEST and POLICY_KEY_SEND.
Added test case for POLICY_KEY_DIGEST and POLICY_KEY_SEND.

arthurprs/aerospike-client-python,aerospike/aerospike-client-python,trupty/aerospike-client-python,trupty/aerospike-client-python,trupty/aerospike-client-python,arthurprs/aerospike-client-python,arthurprs/aerospike-client-python,aerospike/aerospike-client-python,aerospike/aerospike-client-python